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Sample records for external germinal layer

  1. Ectopic overexpression of engrailed-2 in cerebellar Purkinje cells causes restricted cell loss and retarded external germinal layer development at lobule junctions.

    Science.gov (United States)

    Baader, S L; Sanlioglu, S; Berrebi, A S; Parker-Thornburg, J; Oberdick, J

    1998-03-01

    Members of the En and Wnt gene families seem to play a key role in the early specification of the brain territory that gives rise to the cerebellum, the midhindbrain junction. To analyze the possible continuous role of the En and Wnt signaling pathway in later cerebellar patterning and function, we expressed En-2 ectopically in Purkinje cells during late embryonic and postnatal cerebellar development. As a result of this expression, the cerebellum is greatly reduced in size, and Purkinje cell numbers throughout the cerebellum are reduced by more than one-third relative to normal animals. Detailed analysis of both adult and developing cerebella reveals a pattern of selectivity to the loss of Purkinje cells and other cerebellar neurons. This is observed as a general loss of prominence of cerebellar fissures that is highlighted by a total loss of sublobular fissures. In contrast, mediolateral patterning is generally only subtly affected. That En-2 overexpression selectively affects Purkinje cells in the transition zone between lobules is evidenced by direct observation of selective Purkinje cell loss in certain fissures and by the observation that growth and migration of the external germinal layer (EGL) is selectively retarded in the deep fissures during early postnatal development. Thus, in addition to demonstrating the critical role of Purkinje cells in the generation and migration of granule cells, the heterogeneous distribution of cellular effects induced by ectopic En expression suggests a relatively late morphogenetic role for this and other segment polarity proteins, mainly oriented at lobule junctions.

  2. RBP-J is not required for granule neuron progenitor development and medulloblastoma initiated by Hedgehog pathway activation in the external germinal layer

    Directory of Open Access Journals (Sweden)

    Hallahan Andrew R

    2010-10-01

    Full Text Available Abstract Background The Notch signalling pathway plays crucial roles in neural development, functioning by preventing premature differentiation and promotion of glial cell fates. In the developing cerebellum Notch pathway components are expressed in granule neuron progenitors of the external germinal layer (EGL but the precise function of Notch in these cells is unclear. The Hedgehog pathway is also crucial in cerebellar development, mainly via control of the cell cycle, and persistent activation of the pathways leads to the cerebellar tumour medulloblastoma. Interactions between Hedgehog and Notch have been reported in normal brain development as well as in Hedgehog pathway induced medulloblastoma but the molecular details of this interaction are not known and we investigate here the role of Notch signalling in the development of the EGL and the intersection between the two pathways in cerebellar granule neuron progenitors and in medulloblastoma. Results RBP-J is the major downstream effector of all four mammalian Notch receptors and the RBP-J conditional mouse facilitates inactivation of canonical Notch signals. Patched1 is a negative regulator of Hedgehog signalling and the Patched1 conditional mouse is widely used to activate Hedgehog signalling via Patched1 deletion in specific cell types. The conditional mouse lines were crossed with a Math1-Cre line to delete the two genes in granule neuron progenitors from embryonic day 10.5. While deletion of only Patched1 as well as Patched1 together with RBP-J leads to formation of medulloblastoma concomitant with disorganisation of cell layers, loss of RBP-J from granule neuron progenitors has no obvious effect on overall cerebellar morphology or differentiation and maturation of the different cerebellar cell types. Conclusions Our results suggest that even though Notch signalling has been shown to play important roles in cerebellar development, signalling via RBP-J is surprisingly not required in

  3. Development of a cell line from Echinococcus granulosus germinal layer.

    Science.gov (United States)

    Albani, Clara María; Cumino, Andrea Carina; Elissondo, María Celina; Denegri, Guillermo María

    2013-10-01

    In vitro culture of parasitic helminths provides an important tool to study cell regeneration and physiology, as well as for molecular biology and genetic engineering studies. In the present study, we established in vitro propagation of cells from Echinococcus granulosus germinal cyst layer. E. granulosus germinal cells grew beyond 100 passages and showed no signs of reduced proliferation capacity. Microscopic analysis revealed that cells grew both attached to the substrate and in suspension, forming three-dimensional structures like mammalian stem cell aggregates. Examination of the chromosome number of attached germinal cells showed a high degree of heteroploidy, suggesting the occurrence of transformation during culture. Monolayer cells survived cryopreservation and were able to proliferate after thawing. Based on the characteristics displayed by E. granulosus germinal cells, we establish a cell line from the E. granulosus germinal layer. Furthermore, we propose that this cell line could be useful for drug screening and for obtaining parasite material.

  4. Adult neurogenesis without germinal layers: the "atypical" cerebellum of rabbits.

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    Ponti, G; Crociara, P; Armentano, M; Bonfanti, L

    2010-06-01

    Unlike non mammalian vertebrates, adult neurogenesis in mammals is detectable in highly restricted brain sites. Persistent neurogenesis is thought to depend on stem cells residing in neural stem cell niches which are remnants of the embryonic germinal layers. Local progenitors which retain some proliferative capacity have been identified in the mature brain parenchyma, yet they do not support a constitutive, 'actual' neurogenesis, but rather a 'potential' neurogenesis which does not extrinsecate fully and spontaneously in vivo. In contrast with such a view, genesis of neuronal and glial cells from local progenitors does occur in the peripuberal and adult rabbit cerebellum. This process is independent from persisting germinal layers and involves different cell populations.

  5. Divergent responses to thyroid hormone treatment of the different secondary germinal layers in the postnatal rat brain.

    Science.gov (United States)

    Seress, L

    1978-01-01

    The effect of daily triiodothyronine (T3) treatment (first injection on the day of birth) was studied on the postnatal development of various parts of the rat brain. It was found that the T3 treatment resulted in an increase of the cell multiplication in the external grannular layer of the cerebellum but decreased the cell division or had no significant effect in the periventricular germinal layer and in the polymorph layer of the dentate gyrus. From the 10th day the T3 treatment resulted in a decrease of the cell division in all secondary germinal layers examined. As a reason for this different effect is can be suggested that the triidothyronine acts differently upon the various neuronal and glial precursors or upon the germinal layers producing them.

  6. Cystic degeneration of the telencephalic subependymal germinal layer in newborn infants.

    Science.gov (United States)

    De León, G A; Girling, D J

    1975-03-01

    Cystic lesions were found in the telencephalic germinal layer of 12 newborn babies. According to their location, the cysts could be divided into three groups: anterior, middle or thalamostriate, and posterior. The histological appearance of all cysts was essentially the same, but in three cases the germinal layer had a peculiar alveolar type of microcystic degeneration. A constant feature was the presence in the cyst wall of small white granulations composed of germinal cells and/or glial tissue. Cystic degeneration of the germinal layer was usually bilateral and sometimes quite extensive. After the involution of the germinal layer, these lesions are likely to persist as subependymal cysts, characterized by their specific location and the presence of glial granulations.

  7. Discrete domains of gene expression in germinal layers distinguish the development of gyrencephaly

    OpenAIRE

    de Juan Romero, Camino; Bruder, Carl; Tomasello, Ugo; Sanz-Anquela, José Miguel; Borrell, Víctor

    2015-01-01

    Gyrencephalic species develop folds in the cerebral cortex in a stereotypic manner, but the genetic mechanisms underlying this patterning process are unknown. We present a large-scale transcriptomic analysis of individual germinal layers in the developing cortex of the gyrencephalic ferret, comparing between regions prospective of fold and fissure. We find unique transcriptional signatures in each germinal compartment, where thousands of genes are differentially expressed between regions, inc...

  8. Glial differentiation in the germinal layer of fetal and preterm infant brain: an immunocytochemical study.

    Science.gov (United States)

    Gould, S J; Howard, S

    1988-01-01

    The germinal layer in preterm infants is a common site of intracerebral hemorrhage that is associated with increased mortality and morbidity in survivors. This matrix is composed of a mass of immature cells containing many thin-walled blood vessels. A major factor in the occurrence of hemorrhage at this site is the absence of a network of fibers to support these vessels. This immunocytochemical study has examined glial differentiation within the germinal layer of brains from fetuses and preterm infants of gestational ages 18 to 35 weeks. Progressive glial differentiation with gestation is described. This process is not uniform and the more posterior germinal layer, lying over the body of the caudate nucleus, demonstrates more rapid maturation than that lying anteriorly near the head of the caudate nucleus. Anteriorly, even at 35 weeks of gestation, a central core of germinal layer cells remains immature with little evidence of glial differentiation. These changes may be related to the occurrence and distribution of germinal layer hemorrhages in preterm infants of varying gestations.

  9. Discrete domains of gene expression in germinal layers distinguish the development of gyrencephaly.

    Science.gov (United States)

    de Juan Romero, Camino; Bruder, Carl; Tomasello, Ugo; Sanz-Anquela, José Miguel; Borrell, Víctor

    2015-07-14

    Gyrencephalic species develop folds in the cerebral cortex in a stereotypic manner, but the genetic mechanisms underlying this patterning process are unknown. We present a large-scale transcriptomic analysis of individual germinal layers in the developing cortex of the gyrencephalic ferret, comparing between regions prospective of fold and fissure. We find unique transcriptional signatures in each germinal compartment, where thousands of genes are differentially expressed between regions, including ~80% of genes mutated in human cortical malformations. These regional differences emerge from the existence of discrete domains of gene expression, which occur at multiple locations across the developing cortex of ferret and human, but not the lissencephalic mouse. Complex expression patterns emerge late during development and map the eventual location of folds or fissures. Protomaps of gene expression within germinal layers may contribute to define cortical folds or functional areas, but our findings demonstrate that they distinguish the development of gyrencephalic cortices.

  10. Effect of externally generated turbulence on wave boundary layer

    DEFF Research Database (Denmark)

    Fredsøe, Jørgen; Sumer, B. Mutlu; Kozakiewicz, A.

    2003-01-01

    This experimental study deals with the effect of externally generated turbulence on the oscillatory boundary layer to simulate the turbulence in the wave boundary layer under broken waves in the swash zone. The subject has been investigated experimentally in a U-shaped, oscillating water tunnel...... with a smooth bottom. Turbulence was generated ´externally´ as the flow in the oscillator was passed through a series of grids, that extended from the cover of the water tunnel to about mid-depth. Two different types of grid porosities were used. Direct measurements of the bed shear stress and velocity...... results. The mean and turbulence quantities in the outer flow region are increased substantially with the introduction of the grids. It is shown that the externally generated turbulence is able to penetrate the bed boundary layer, resulting in an increase in the bed shear stress, and therefore...

  11. External foam layers to football helmets reduce head impact severity.

    Science.gov (United States)

    Nakatsuka, Austin S; Yamamoto, Loren G

    2014-08-01

    Current American football helmet design has a rigid exterior with a padded interior. Softening the hard external layer of the helmet may reduce the impact potential of the helmet, providing extra head protection and reducing its use as an offensive device. The objective of this study is to measure the impact reduction potential provided by external foam. We obtained a football helmet with built-in accelerometer-based sensors, placed it on a boxing mannequin and struck it with a weighted swinging pendulum helmet to mimic the forces sustained during a helmet-to-helmet strike. We then applied layers of 1.3 cm thick polyolefin foam to the exterior surface of the helmets and repeated the process. All impact severity measures were significantly reduced with the application of the external foam. These results support the hypothesis that adding a soft exterior layer reduces the force of impact which may be applicable to the football field. Redesigning football helmets could reduce the injury potential of the sport.

  12. In situ analyses of gallstone inner layers by external PIXE

    Science.gov (United States)

    Rautray, Tapash R.; Dutta, Koushik; Das, Saubhagya L.; Rautray, Alekh C.

    2010-09-01

    External proton induced X-ray emission analyses were carried out to study the elemental profile at different points of two mixed gallstones inner layers. It was observed that ten minor/trace elements namely P, S, Ca, Mn, Fe, Cu, Zn, Br, Rb and Sr were present in the mixed gallstone layers. Among the elements detected, Ca shows the highest concentration whereas Br, Rb and Sr were found only at some points in trace level. Concentrations of Ca and P were observed to be the highest in the core of the gallstones. The presence of high amount of Cu and Zn on the surface of the gallstones, as compared to other layers, may be due to contamination with bile.

  13. In situ analyses of gallstone inner layers by external PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Rautray, Tapash R., E-mail: tapash77@hotmail.co [Department of Dental Biomaterials, School of Dentistry, Kyungpook National University, 2-188-1 Samduk-dong, Jung-gu, Daegu (Korea, Republic of); Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); ARASMIN, G. Udayagiri, Kandhamal, Orissa 762100 (India); Dutta, Koushik; Das, Saubhagya L. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005 (India); Rautray, Alekh C. [ARASMIN, G. Udayagiri, Kandhamal, Orissa 762100 (India)

    2010-09-15

    External proton induced X-ray emission analyses were carried out to study the elemental profile at different points of two mixed gallstones inner layers. It was observed that ten minor/trace elements namely P, S, Ca, Mn, Fe, Cu, Zn, Br, Rb and Sr were present in the mixed gallstone layers. Among the elements detected, Ca shows the highest concentration whereas Br, Rb and Sr were found only at some points in trace level. Concentrations of Ca and P were observed to be the highest in the core of the gallstones. The presence of high amount of Cu and Zn on the surface of the gallstones, as compared to other layers, may be due to contamination with bile.

  14. Echinococcus granulosus: DNA extraction from germinal layers allows strain determination in fertile and nonfertile hydatid cysts.

    Science.gov (United States)

    Kamenetzky, L; Canova, S G; Guarnera, E A; Rosenzvit, M C

    2000-06-01

    A method for the isolation of Echinococcus granulosus DNA from germinal layers of hydatid cysts is described. The method includes a hexadecyltrimethylammonium bromide/chloroform extraction and an adsorption to diatomaceous earth suspension. DNA suitable for polymerase chain reaction was obtained and used for parasite strain determination by mitochondrial cytochrome c oxidase I gene sequencing. Fertile and nonfertile cyst isolates from sheep, cattle, pigs, and humans were characterized. Hitherto, no direct parasite strain characterization has been made on nonfertile hydatid cysts, whereas here we report that nonfertile hydatid cysts were produced by sheep strain (G1 genotype) in sheep, cattle, and humans and by pig strain (G7 genotype) in pigs.

  15. The effects of external conditions in turbulent boundary layers

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    Brzek, Brian G.

    The effects of multiple external conditions on turbulent boundary layers were studied in detail. These external conditions include: surface roughness, upstream turbulence intensity, and pressure gradient. Furthermore, the combined effects of these conditions show the complicated nature of many realistic flow conditions. It was found that the effects of surface roughness are difficult to generalize, given the importance of so many parameters. These parameters include: roughness geometry, roughness regime, roughness height to boundary layer thickness, (k/delta), roughness parameter, ( k+), Reynolds number, and roughness function (Delta B+). A further complication, is the difficulty in computing the wall shear stress, tauw/rho. For the sand grain type roughness, the mean velocity and Reynolds stresses were studied in inner and outer variables, as well as, boundary layer parameters, anisotropy tensor, production term, and viscous stress and form drag contributions. To explore the effects of roughness and Reynolds number dependence in the boundary layer, a new experiment was carefully designed to properly capture the x-dependence of the single-point statistics. It was found that roughness destroys the viscous layer near the wall, thus, reducing the contribution of the viscous stress in the wall region. As a result, the contribution in the skin friction due to form drag increases, while the viscous stress decreases. This yields Reynolds number invariance in the skin friction, near-wall roughness parameters, and inner velocity profiles as k + increases into the fully rough regime. However, in the transitionally rough regime, (i.e., 5 component shows the largest influence of roughness, where the high peak near the wall was decreased and became nearly flat for the fully rough regime profiles. In addition, the Reynolds stresses in outer variables show self-similarity for fixed experimental conditions. However, as the roughness parameter, k +, increases, all Reynolds stress

  16. Epidermis contains platelet-type 12-lipoxygenase that is overexpressed in germinal layer keratinocytes in psoriasis.

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    Hussain, H; Shornick, L P; Shannon, V R; Wilson, J D; Funk, C D; Pentland, A P; Holtzman, M J

    1994-01-01

    Human epidermal cells exhibited none of the cytosolic lipoxygenase activity that is prominent in mucosal epithelial cells, but instead contained a microsomal activity that converted arachidonic acid to 12-hydroxyeicosatetraenoic acid (12-HETE). Identification of the extractable 12-HETE-forming activity as a 12-lipoxygenase (distinct from cytochrome P-450) included (S)-12-stereospecificity of product formation, trapping of 12-hydroperoxyeicosatetraenoic acid as an intermediate reaction product, and lack of NADPH dependence for activity. Epidermal cell poly(A)+ RNA contained high levels of a 2.3-kb mRNA that selectively hybridized with human platelet 12-lipoxygenase cDNA, and partial cDNA sequence of this mRNA indicated identity to platelet 12-lipoxygenase. The epidermal 12-lipoxygenase was not recognized by antibodies against the leukocyte-type 12- and 15-lipoxygenases (found in leukocytes, reticulocytes, and mucosal epithelial cells) but was detected by an antiplatelet 12-lipoxygenase antibody. The epidermal 12-lipoxygenase antigen was selectively expressed in germinal layer keratinocytes in healthy and psoriatic skin, and these layers exhibited hyperplasia and increased immunostaining in inflamed psoriatic skin. Together with previous results, these observations indicate that 1) epidermis generates 12-HETE by either cytochrome P-450 or lipoxygenase-based mechanisms depending on reaction conditions, and 2) 12-lipoxygenases (originally described in hematopoietic cell types) may be expressed in at least two distinct isoforms in epithelial barriers in humans, and in the case of the skin, a microsomal (platelet-type) 12-lipoxygenase is selectively overexpressed in germinal layer keratinocytes during psoriatic inflammation.

  17. Bending of Layer-by-Layer Films Driven by an External Magnetic Field

    Directory of Open Access Journals (Sweden)

    Osvaldo N. Oliveira Jr.

    2013-06-01

    Full Text Available We report on optimized architectures containing layer-by-layer (LbL films of natural rubber latex (NRL, carboxymethyl-chitosan (CMC and magnetite (Fe3O4 nanoparticles (MNPs deposited on flexible substrates, which could be easily bent by an external magnetic field. The mechanical response depended on the number of deposited layers and was explained semi-quantitatively with a fully atomistic model, where the LbL film was represented as superposing layers of hexagonal graphene-like atomic arrangements deposited on a stiffer substrate. The bending with no direct current or voltage being applied to a supramolecular structure containing biocompatible and antimicrobial materials represents a proof-of-principle experiment that is promising for tissue engineering applications in biomedicine.

  18. External serial connection without layer patterning for organic solar cells

    Science.gov (United States)

    Wong, Ying Qian; Wong, Hin Yong; Tan, Ching Seong; Meng, Hsin-Fei

    2016-12-01

    This paper proposes a novel alternative to conventional internal serial connection, where precise patterning and scribing of organic layers can be eliminated. Adjacent cells can be made nearer for better space-utilization and higher voltages per unit area. Also, blade coating is proposed as the fabrication method as it has low material wastage (less than 5%), easily scalable to large area, has high film uniformity and has high throughput due to its roll-to-roll potential. This paper demonstrates 3-cells large area (12.98 cm2) external serial connection organic solar cells (OSCs) using the material poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) and 2,6-Bis(trimethyltin)-4, 8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo [1,2-b:4,5-b']dithiophene:6,6-phenyl C71-butyric acid methyl ester (PBDTTT-CT:PC71BM) respectively. The power conversion efficiencies (PCEs) of the resulting 3-cells modules are 2.0% and 4.1% respectively.

  19. An immunocytochemical study of the germinal layer vasculature in the developing fetal brain using Ulex europaeus 1 lectin.

    Science.gov (United States)

    Gould, S J; Howard, S

    1988-10-01

    The characteristics of the germinal matrix vasculature were studied in the developing fetal brain using immunocytochemical methods. A preliminary comparative immunocytochemical study was made on six fetal brains to compare endothelial staining by Ulex europaeus I lectin with that of antibody to Factor VIII related antigen. Ulex was found to stain germinal layer vessels better than Factor VIII related antigen. Subsequently, the germinal layers of a further 15 fetal and preterm infant brains ranging from 13 to 35 weeks' gestation were stained with Ulex europaeus I to demonstrate the vasculature. With increasing gestation, there was a gradual increase in vessel density, particularly of capillaries. This was not a uniform process. A plexus of capillaries was prominent immediately beneath the ependyma while the more central parts of the germinal matrix contained fewer, but often larger diameter, vessels. The variation in vessel density which was a feature of the later gestation brains may have implications for local blood flow and may be a factor in haemorrhage at this site.

  20. Dendrodendritic Synapses in the Mouse Olfactory Bulb External Plexiform Layer

    Science.gov (United States)

    Bartel, Dianna L.; Rela, Lorena; Hsieh, Lawrence; Greer, Charles A.

    2014-01-01

    Odor information relayed by olfactory bulb projection neurons, mitral and tufted cells (M/T), is modulated by pairs of reciprocal dendrodendritic synaptic circuits in the external plexiform layer (EPL). Interneurons, which are accounted for largely by granule cells, receive depolarizing input from M/T dendrites and in turn inhibit current spread in M/T dendrites via hyperpolarizing reciprocal dendrodendritic synapses. Because the location of dendrodendritic synapses may significantly affect the cascade of odor information, we assessed synaptic properties and density within sublaminae of the EPL and along the length of M/T secondary dendrites. In electron micrographs the M/T to granule cell synapse appeared to predominate and were equivalent in both the outer and inner EPL. However, the dendrodendritic synapses from granule cell spines onto M/T dendrites, were more prevalent in the outer EPL. In contrast, individual gephyrin-IR puncta, a postsynaptic scaffolding protein at inhibitory synapses used here as a proxy for the granule to M/T dendritic synapse was equally distributed throughout the EPL. Of significance to the organization of intrabulbar circuits, gephyrin-IR synapses are not uniformly distributed along M/T secondary dendrites. Synaptic density, expressed as a function of surface area, increases distal to the cell body. Furthermore, the distributions of gephyrin-IR puncta are heterogeneous and appear as clusters along the length of the M/T dendrites. Consistent with computational models, our data suggest that temporal coding in M/T cells is achieved by precisely located inhibitory input and that distance from the soma is compensated with an increase in synaptic density. PMID:25420934

  1. Cells of embryonic and regenerating germinal layers within barb ridges: implication for the development, evolution and diversification of feathers.

    Science.gov (United States)

    Alibardi, L

    2006-04-01

    The formation of feathers occurs by the transformation of the embryonic epidermis of feather filaments into keratinized barbules and barbs. The present ultrastructural study directly documents this transformation in chick and zebrafinch downfeathers and juvenile feathers. The transformation of the epidermis in the feather filament (downfeathers) or in the follicle (juvenile feathers) is similar. The change in cell shape of subperiderm or subsheath cells and surrounding barb vane ridge cells derives from the re-organization of the linear embryonic epithelium into barb ridges. In the latter the stratification of the outer and inner periderm, of the subperiderm/subsheath, and of the germinal layer of the embryonic epidermis is altered. While the external layers produce the sheath and barb vane ridge cells, subperiderm/subsheath cells are displaced into barbule plates that converge medially in the ramus area of the barb ridge. Cells in the barbule plates elongate into barbule and barb cortical cells by the synthesis of longitudinally oriented feather keratin bundles. In the mid-central area of the barb ridge (the ramus area) cells become polygonal and pile up. The external cells accumulate numerous keratin filaments forming cortical cells and are in contact with barbule cells. The above process also occurs in barb ridges of juvenile feathers and of adult feathers before molting. However, barb ridges produced within follicles of juveniles and adult feathers are longer than in downfeathers, and possess long rami. The incorporation of tritiated histidine in barbule and barb cortical cells has been studied by ultrastructural autoradiography. Most of the labeling is cytoplasmic or is associated with bundles of keratin but is not concentrated over keratin. This indicates that together with keratin possible histidine-rich keratin-associated proteins are produced during the elongation from subperiderm/subsheath to barbule/barb cells. Barb cortical cells merge with medullary

  2. Analysis of Air Flow in the Ventilated Insulating Air Layer of the External Wall

    Science.gov (United States)

    Katunská, Jana; Bullová, Iveta; Špaková, Miroslava

    2016-12-01

    The paper deals with problems of impact of air flow in ventilated insulating air layer of the external wall on behaviour of thermal-technical parameters of the proposed external structure (according principles of STN 73 0549, which is not valid now), by comparing them in the calculation according to the valid STN standards, where air flow in the ventilated air layer is not taken into account, as well as by comparing them with behavior of thermal-technical parameters in the proposal of sandwich external wall with the contact heat insulation system without air cavity.

  3. Effect of externality in multiplex networks on one-layer synchronization

    Science.gov (United States)

    Jiang, Xin; Li, Meng; Zheng, Zhiming; Ma, Yifang; Ma, Lili

    2015-06-01

    Synchronization phenomenon plays an important role in the dynamic process on complex networks. In this letter, we consider synchronization under multiplex structures and explore the effect of external parts on the multilayered Kuramoto model with positive correlation between frequencies and degree. We show that large and strong mixing parts of the external layer may put off synchronization while the coupling strength of external layers has an accelerating, but limited, influence on synchronization. In particular, an explosive synchronization can be obtained by weakening the co-evolution coupling strength. The transition tends to be smooth when the co-evolution coupling strength increases. Our findings indicate that externality from multiplex networks, especially the mixing parts, and the co-evolution coupling strength should be of importance for synchronization on one certain layer.

  4. Characterization of macrophage-like cells in the external layers of human small and large intestine

    DEFF Research Database (Denmark)

    Mikkelsen, H B; Rumessen, J J

    1992-01-01

    -DR-positive (expressing the MHC class-II antigen), in contrast to macrophage-like cells in the subserosa and submucosa. Macrophage-like cells in the external muscle layer were mostly acid phosphatase-negative, and at the electron-microscopic level they were found to have features of macrophages: primary lysosomes, coated...... vesicles and pits. However, very few secondary lysosomes were present. Birbeck granules were not observed. It is concluded that in the external muscle layer of human small and large intestine numerous macrophages of a special type are present. It is discussed whether this cell type plays a role...

  5. External Quantum Efficiency Improvement with Luminescent Downshifting Layers: Experimental and Modelling

    OpenAIRE

    Ahmed, H.; S. J. McCormack; Doran, J.

    2016-01-01

    Core-shell quantum dots CdSe/ZnS and lumogen yellow organic dye are characterized by their inclusion in luminescent downshifting (LDS) layers. Layers were deposited on top of crystalline silicon cell (c-Si), dye synthesized solar cell (DSSC), and cadmium telluride (CdTe) minimodules. External quantum efficiency measurements for the solar cell/LDS devices are discussed. Experimental results were compared with an optical model developed by Rothemund, 2014.

  6. External Quantum Efficiency Improvement with Luminescent Downshifting Layers: Experimental and Modelling

    Directory of Open Access Journals (Sweden)

    H. Ahmed

    2016-01-01

    Full Text Available Core-shell quantum dots CdSe/ZnS and lumogen yellow organic dye are characterized by their inclusion in luminescent downshifting (LDS layers. Layers were deposited on top of crystalline silicon cell (c-Si, dye synthesized solar cell (DSSC, and cadmium telluride (CdTe minimodules. External quantum efficiency measurements for the solar cell/LDS devices are discussed. Experimental results were compared with an optical model developed by Rothemund, 2014.

  7. Effect of buffer layer and external stress on magnetic properties of flexible FeGa films

    Science.gov (United States)

    Zhang, Xiaoshan; Zhan, Qingfeng; Dai, Guohong; Liu, Yiwei; Zuo, Zhenghu; Yang, Huali; Chen, Bin; Li, Run-Wei

    2013-05-01

    We systematically investigated the effect of a Ta buffer layer and external stress on the magnetic properties of magnetostrictive Fe81Ga19 films deposited on flexible polyethylene terephthalate (PET) substrates. The Ta buffer layers could effectively smoothen the rough surface of PET. As a result, the FeGa films grown on Ta buffer layers exhibit a weaker uniaxial magnetic anisotropy and lower coercivity, as compared to those films directly grown on PET substrates. By inward and outward bending the FeGa/Ta/PET samples, external in-plane compressive and tensile stresses were applied to the magnetic films. Due to the inverse magnetostrictive effect of FeGa, both the coercivity and squareness of hysteresis loops for FeGa/Ta films could be well tuned under various strains.

  8. Primary hydatid cyst of the supraspinatus muscle: complete removal of the germinal layer and cytodiagnosis by fine-needle aspiration.

    Science.gov (United States)

    Das, Dilip K; El-Sharawy, Maha; Ayyash, Emad H; Al-Enezi, Nadia A; Iqbal, Jamshed R; Madda, John P

    2014-03-01

    Primary hydatid disease of the skeletal muscle without systemic involvement is rare. The purpose of this report is to document the novel clinical presentation and the interesting facets of fine-needle aspiration in a case of hydatid disease. It was a case of primary hydatid cyst of the left supraspinatus muscle in an Indian woman living in Kuwait, which was clinically diagnosed as a lipoma. Fine-needle aspiration (FNA) yielded 2 ml of clear fluid with white particulate material. The cytocentrifuged smears prepared from the aspirated fluid showed many scolices, occasional laminated cyst wall fragments and numerous hooklets. The laminated cyst wall and scolices were PAS positive. Trichrome staining imparted a demon-head-like appearance to the scolices. The cytodiagnosis of hydatid cyst was corroborated by histopathological examination of an excised whitish membrane and an irregular cystic fragment, which showed parallel laminations without germinal layer, and skeletal muscle with granulomas and a dense eosinophilic infiltration, respectively. Quantitative serological (indirect hemagglutination) test on blood sample collected 9 days after the excision of the cyst showed insignificant antibody titer to Echinococcus sp. and after 6 weeks the antibodies were completely absent. CT scan of the chest and abdomen performed 7 weeks after removal of cyst showed no evidence of visceral hydatid cyst.

  9. Numerical evaluation of external magnetic effect on electromagnetic wave transmission through reentry plasma layer

    Science.gov (United States)

    Zhao, Qing; Bo, Yong; Lei, Mingda; Liu, Shuzhang; Liu, Ying; Liu, Jianwei; Zhao, Yizhe

    2016-11-01

    Numerical study of electromagnetic (EM) wave transmission through the magnetized plasma layer is presented in this paper. The plasma parameters are derived from computational fluid dynamics simulation of the flow field around a blunt body flying at supersonic speed and serve as the background plasma condition in the numerical modeling for EM wave transmission. The EM wave is generated by our newly designed coaxial feed GPS patch antenna. The external magnetic field is applied and assumed to vary linearly as a function of wall distance. The effects of the external applied magnetic field and the plasma parameters on wave transmission are studied, and the results show that EM wave propagation in the non-uniformly magnetized plasma is a matter of impedance matching, and the EM wave transmission can be adjusted only when the proper strength of the magnetic field is applied.

  10. Similarity Solutions of Marangoni Convection Boundary Layer Flow with Gravity and External Pressure

    Institute of Scientific and Technical Information of China (English)

    张艳; 郑连存

    2014-01-01

    This study is focused on a steady dissipative layer, which is generated by Marangoni convection flow over the surface resulted from an imposed temperature gradient, coupled with buoyancy effects due to gravity and external pressure. A model is proposed with Marangoni condition in the boundary conditions at the interface. The similarity equations are determined and approximate analytical solutions are obtained by an efficient transformation, asymptotic expansion and Padé approximant technique. For the cases that buoyancy force is favorable or unfavor-able to Marangoni flow, the features of flow and temperature fields are investigated in terms of Marangoni mixed convection parameter and Prantl number.

  11. Effect of the External Lubrication Method for a Rotary Tablet Press on the Adhesion of the Film Coating Layer.

    Science.gov (United States)

    Kondo, Hisami; Toyota, Hiroyasu; Kamiya, Takayuki; Yamashita, Kazunari; Hakomori, Tadashi; Imoto, Junko; Kimura, Shin-Ichiro; Iwao, Yasunori; Itai, Shigeru

    2017-01-01

    External lubrication is a useful method which reduces the adhesion of powder to punches and dies by spraying lubricants during the tableting process. However, no information is available on whether the tablets prepared using an external lubrication system can be applicable for a film coating process. In this study, we evaluated the adhesion force of the film coating layer to the surface of tablets prepared using an external lubrication method, compared with those prepared using internal lubrication method. We also evaluated wettability, roughness and lubricant distribution state on the tablet surface before film coating, and investigated the relationship between peeling of the film coating layer and these tablet surface properties. Increasing lubrication through the external lubrication method decreased wettability of the tablet surface. However, no change was observed in the adhesion force of the film coating layer. On the other hand, increasing lubrication through the internal lubrication method, decreased both wettability of the tablet surface and the adhesion force of the film coating layer. The magnesium stearate distribution state on the tablet surface was assessed using an X-ray fluorescent analyzer and lubricant agglomerates were observed in the case of the internal lubrication method. However, the lubricant was uniformly dispersed in the external lubrication samples. These results indicate that the distribution state of the lubricant affects the adhesion force of the film coating layer, and external lubrication maintained sufficient lubricity and adhesion force of the film coating layer with a small amount of lubricant.

  12. Age effect of male and female broiler breeders on sperm penetration of the perivitelline layer overlying the germinal disc.

    Science.gov (United States)

    Bramwell, R K; McDaniel, C D; Wilson, J L; Howarth, B

    1996-06-01

    An experiment was conducted to test the effect of age (male and female) on the number of spermatozoa penetrating the perivitelline layer (PL) overlying the germinal disc (GD) in broiler breeders. Eighty young broiler breeder hens (39 wk old, Y), and 80 old spent broiler breeder hens (69 wk old, O) were randomly divided into eight groups of 20 hens each by age. Hens were inseminated weekly for 4 consecutive wk with 5 x 10(7) pooled sperm/50 microL from either young or old broiler breeder males. Sperm penetration (SP) of the PL at the GD was assessed in a random sample of 12 oviposited eggs from each hen group for each day postinsemination, with the remainder of the eggs incubated for 10 d to obtain fertility values. For the main effect of sex, and for age within sex, there were differences in mean SP (7.3 vs 4.8; Y vs O hens; P hens; P artificial insemination of a constant number of sperm, age of hens appears to contribute more to the decrease in SP and fertility than the age of male broiler breeders. Eggs were obtained from naturally mated broiler breeder flocks from different strains (A and B), lines (male and female), and ages. There was an effect on overall mean SP values due to strain (105.8 vs 78.6 holes per GD area; Strains A and B, respectively; P < 0.0001), and line within Strain B (106.4 vs 50.8 holes per GD; male and female line, respectively; P < 0.0001). There was a quadratic relationship between SP of the PL and age in Strain A with values ranging from 153.3 to 20.0 holes per GD area (P < 0.003). In Strain B, SP holes in the PL decreased in the male line due to age (127.8 to 59.7 per GD; P < 0.01), with an effect of age on the female line also (62.1 vs. 37.8 holes per GD; P < 0.05).

  13. Drag reduction for external and internal boundary layers using riblets and polymers

    Science.gov (United States)

    Reidy, Laurel W.; Anderson, Greg W.

    1988-01-01

    The efficiency of riblets and a drag-reducing polymer solution (a polyacrylamide slurry) in high-speed water tunnels for reducing drag in turbulent boundary layers was investigated in two experiments. One was an external flow experiment, in which riblets were applied to a flat plate in a high-speed water tunnel and the skin friction drag was calculated from velocity profile data. The second was an internal flow experiment, in which riblets were applied to the inside of a 6-in diameter pipe and the friction factor was calculated from mass flow rate and pressure drop measurements. Both experiments used adhesive-backed vinyl riblet film with 0.003-in height and spacing of the symmetric V-grooves. For the flat plate test, free stream velocity and Re data indicated a maximum drag reduction of about 8.1 percent. With riblets in the pipe, however, there was about three times as much friction reduction. When the polymer slurry was used in conjunction with riblets in the pipe flow, the total drag reduction was approximately equal to the sum of the drag reductions of the two techniques used separately, with some dependence on Reynolds number.

  14. The research and preparation of a bi-layer biodegradable external sheath with directional drug release profiles for vein graft

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhenjie, E-mail: lawson3001@gmail.com [Department of Surgery, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou (China); Institute of Vascular Surgery, Fudan University, Shanghai (China); Department of Surgery, University of Wisconsin-Madison, WI (United States); Guo, Zhenying [Department of Pathology, Zhejiang Cancer Hospital, Hangzhou (China); Si, Yi [Department of Surgery, University of Wisconsin-Madison, WI (United States); Zhang, Xiangman; Shi, Zhenyu [Institute of Vascular Surgery, Fudan University, Shanghai (China); Chen, Feng [College of Chemical Engineering and Material Science, Zhejiang University of Technology, Hangzhou (China); Fu, Weiguo [Institute of Vascular Surgery, Fudan University, Shanghai (China)

    2013-11-01

    External sheath has been suggested for autologous vein grafts to inhibit neointimal hyperplasia and prevent anastomosis stricture. In this study, we prepared a bi-layer biodegradable paclitaxel-loaded sheaths with a synthetic copolymer poly(ethylene carbonate-ε-caprolactone) at room temperature. The bi-layer drug release profiles of the Paclitaxel-loaded (PTX-loaded) sheath significantly slow down the paclitaxel (PTX) release rates and result in a directional drug release way. Moreover, the nanofibrous layer of PTX-loaded poly(EC-CL) sheaths reduced the cytotoxicity and provided a better support for fibroblast adhesion and proliferation than the PTX-loaded layer of the sheaths. Thus, this study demonstrates that the bi-layer PTX-loaded poly(EC-CL) sheath with directional drug release profiles have a promising application for vein graft to against neointimal hyperplasia and anastomotic stricture.

  15. Caracterización y análisis de la actividad antigénica de proteínas de la membrana germinal de Echinococcus granulosus Characterization and antigenic activity of Echinococcus granulosus germinal layer proteins

    Directory of Open Access Journals (Sweden)

    L.H. Prieto

    2006-12-01

    Full Text Available Proteínas presentes en un extracto de membrana germinal de Echinococcus granulosus fueron separadas en una fase acuosa y en una fase detergente mediante el tratamiento con Triton X-114. La caracterización mediante electroforesis en gel de poliacrilamida en presencia de dodecil sulfato de sodio, mostró que proteínas con pesos moleculares aproximados de 102, 45, 28.5-28 y 15.5-15 kDa se presentaron en el extracto y en la fase acuosa (proteínas hidrofílicas. La caracterización inmunológica de proteínas del extracto mediante inmunotransferencia frente a suero ovino no inmunizado, frente a suero ovino inmunizado con antígenos de E. granulosus y frente a suero anti-inmunoglobulina ovina, mostró patrones de reactividad similares. El ensayo inmunodetección en un punto, de proteínas del extracto previamente tratadas con Triton X-114 frente a sueros humanos incubados con el detergente iónico dodecil sulfato de sodio, mostró reactividad frente a sueros humanos con equinococosis quística y no mostró reactividad frente a sueros humanos sin equinococosis quística ni frente a un suero humano infectado con la filaria Mansonella ozzardi.Proteins present in an extract of Echinococcus granulosus germinal layer were separated in hydrophobic and hydrophilic phases using Triton X-114. The characterization carried out by sodium dodecyl sulphate polyacrylamide gel electrophoresis showed that proteins of apparent molecular weights of 102, 45, 28.5-28 and 15.5-15 kDa were present in the extract and in the aqueous phase (hydrophilic proteins. The immunological characterization of extract proteins performed by immunoblotting against to no immunized sheep serum, against to immunized with E. granulosus antigens sheep serum and against to anti-sheep immunoglobulin serum, showed similar reaction patterns. The dot immunobinding assay of extract proteins after Triton X-114 treatment against to human sera incubated in the presence of sodium dodecil sulphate

  16. The use of the external layer of the calvaria's frontal bone to repair craniofacial skeleton injuries in Macaca mulatta (Rhesus

    Directory of Open Access Journals (Sweden)

    Camelo-Nunes José Mário

    2003-01-01

    Full Text Available PURPOSE: To study the integration of the external layer of the calvaria's frontal bone to repair craniofacial skeleton injuries in primates. METHODS: Ten Rhesus monkeys underwent surgery in two stages. In the first stage, four bone fragments were harvested from the external layer of the calvaria's frontal bone and were transplanted two on the calvaria's frontal bone and the other two onto the maxillary bone, by onlay and inlay. Seven weeks thereafter, four fragments were extracted from the transplantated area. The animals were not sacrificed. RESULTS: Macroscopic examination reveals bone regeneration, the areas onto which the bone fragments were transplantated having consequently increased in volume. The results of optical and electron microscopy is being carried out.

  17. Total heat loss coefficient of flat roof constructions with external insulation in tapered layers including the effects of thermal bridges

    DEFF Research Database (Denmark)

    Rose, Jørgen; Svendsen, Svend

    2005-01-01

    and insulation has to be fulfilled. Based on a given design of the tapered insulation the total heat loss coefficient of the roof can be calculated using formulae in EN ISO 6946 for typical segments of the tapered insulation. Performing design and calculations for large roofs with numerous different segments can...... for design of flat roofs and a pc-program that can be used for calculating the total heat loss coefficient of externally insulated roofs with insulation in tapered layers, taking into account thermal bridges in the roof construction.......In order to achieve durability of flat roofs with external insulation, it is necessary to secure proper drainage of the roof, i.e. to avoid water leaking into the insulation. The design of the tapered insulation of the roof is quite difficult as requirements with respect to both drainage...

  18. Total heat loss coefficient of flat roof constructions with external insulation in tapered layers including the effects of thermal bridges

    DEFF Research Database (Denmark)

    Rose, Jørgen; Svendsen, Svend

    2005-01-01

    be quite tedious, and therefore a method to generate and optimize solutions has been developed and implemented in a program that also takes into account the effects of different types of thermal bridges, i.e. roof windows, insulation fasteners, roof/wall joints etc. This paper describes a new method...... for design of flat roofs and a pc-program that can be used for calculating the total heat loss coefficient of externally insulated roofs with insulation in tapered layers, taking into account thermal bridges in the roof construction....

  19. Quasi-two-layer finite-volume scheme for modeling shallow water flows with the presence of external forces

    CERN Document Server

    Karelsky, K V; Slavin, A G

    2011-01-01

    The numerical method for study of hydrodynamic flows over an arbitrary bed profile in the presence of external force is proposed in this paper. This method takes into account the external force effect, it uses the quasi-two-layer model of hydrodynamic flows over a stepwise boundary with consideration of features of the flow near the step. A distinctive feature of the proposed method is the consideration of the properties of the process of the waterfall, namely the fluid flow on the step in which the fluid does not wet part of the vertical wall of the step. The presence of dry zones in the vertical part of the step indicates violation of the conditions of hydrostatic flow. The quasi-two-layer approach allows to determine the size of the dry zone of the vertical component of the step. Consequently it gives an opportunity to figure out the amount of kinetic energy dissipation. There are performed the numerical simulations based on the proposed algorithm of various physical phenomena, such as a breakdown of the r...

  20. Spatio-temporal changes in germination and radical elongation of barley seeds tracked by proteome analysis of dissected embryo, aleurone layer and endosperm tissues

    DEFF Research Database (Denmark)

    Bønsager, Birgit Christine; Finnie, Christine; Roepstorff, P.

    2007-01-01

    Germination of barley is accompanied by changes in water-soluble seed proteins. 2-DE was used to describe spatio-temporal proteome differences in dissected seed tissues associated with germination and the subsequent radicle elongation. Protein identification by MS enabled assignment of proteins...... protein and an ABA-induced protein, suggesting that these proteins are also involved in desiccation stress. Several redox-related proteins differed in spatio-temporal patterns at the end of germination and onset of radicle elongation. Notably, ascorbate peroxidase that was observed only in the embryo......, increased in abundance at 36 h PI. The surprisingly early changes seen in the protein profiles already 4 h after imbibition indicate that germination is programmed during seed maturation...

  1. Perturbation of hydration layer in solvated proteins by external electric and electromagnetic fields: Insights from non-equilibrium molecular dynamics

    Science.gov (United States)

    Nandi, Prithwish K.; Futera, Zdenek; English, Niall J.

    2016-11-01

    Given the fundamental role of water in governing the biochemistry of enzymes, and in regulating their wider biological activity (e.g., by local water concentration surrounding biomolecules), the influence of extraneous electric and electromagnetic (e/m) fields thereon is of central relevance to biophysics and, more widely, biology. With the increase in levels of local and atmospheric microwave-frequency radiation present in modern life, as well as other electric-field exposure, the impact upon hydration-water layers surrounding proteins, and biomolecules generally, becomes a particularly pertinent issue. Here, we present a (non-equilibrium) molecular-dynamics-simulation study on a model protein (hen egg-white lysozyme) hydrated in water, in which we determine, inter alia, translational self-diffusivities for both hen egg-white lysozyme and its hydration layer together with relaxation dynamics of the hydrogen-bond network between the protein and its hydration-layer water molecules on a residue-per-residue basis. Crucially, we perform this analysis both above and below the dynamical-transition temperature (at ˜220 K), at 300 and 200 K, respectively, and we compare the effects of external static-electric and e/m fields with linear-response-régime (r.m.s.) intensities of 0.02 V/Å. It was found that the translational self-diffusivity of hen egg-white lysozyme and its hydration-water layer are increased substantially in static fields, primarily due to the induced electrophoretic motion, whilst the water-protein hydrogen-bond-network-rearrangement kinetics can also undergo rather striking accelerations, primarily due to the enhancement of a larger-amplitude local translational and rotational motion by charged and dipolar residues, which serves to promote hydrogen-bond breakage and re-formation kinetics. These external-field effects are particularly evident at 200 K, where they serve to induce the protein- and solvation-layer-response effects redolent of dynamical

  2. Mixed convection boundary layer flow over a moving vertical flat plate in an external fluid flow with viscous dissipation effect.

    Directory of Open Access Journals (Sweden)

    Norfifah Bachok

    Full Text Available The steady boundary layer flow of a viscous and incompressible fluid over a moving vertical flat plate in an external moving fluid with viscous dissipation is theoretically investigated. Using appropriate similarity variables, the governing system of partial differential equations is transformed into a system of ordinary (similarity differential equations, which is then solved numerically using a Maple software. Results for the skin friction or shear stress coefficient, local Nusselt number, velocity and temperature profiles are presented for different values of the governing parameters. It is found that the set of the similarity equations has unique solutions, dual solutions or no solutions, depending on the values of the mixed convection parameter, the velocity ratio parameter and the Eckert number. The Eckert number significantly affects the surface shear stress as well as the heat transfer rate at the surface.

  3. Novel subdomains of the mouse olfactory bulb defined by molecular heterogeneity in the nascent external plexiform and glomerular layers

    Directory of Open Access Journals (Sweden)

    Yona Golan

    2007-05-01

    Full Text Available Abstract Background In the mouse olfactory system, the role of the olfactory bulb in guiding olfactory sensory neuron (OSN axons to their targets is poorly understood. What cell types within the bulb are necessary for targeting is unknown. What genes are important for this process is also unknown. Although projection neurons are not required, other cell-types within the external plexiform and glomerular layers also form synapses with OSNs. We hypothesized that these cells are important for targeting, and express spatially differentially expressed guidance cues that act to guide OSN axons within the bulb. Results We used laser microdissection and microarray analysis to find genes that are differentially expressed along the dorsal-ventral, medial-lateral, and anterior-posterior axes of the bulb. The expression patterns of these genes divide the bulb into previously unrecognized subdomains. Interestingly, some genes are expressed in both the medial and lateral bulb, showing for the first time the existence of symmetric expression along this axis. We use a regeneration paradigm to show that several of these genes are altered in expression in response to deafferentation, consistent with the interpretation that they are expressed in cells that interact with OSNs. Conclusion We demonstrate that the nascent external plexiform and glomerular layers of the bulb can be divided into multiple domains based on the expression of these genes, several of which are known to function in axon guidance, synaptogenesis, and angiogenesis. These genes represent candidate guidance cues that may act to guide OSN axons within the bulb during targeting.

  4. Neonatal disorders of germinal matrix

    NARCIS (Netherlands)

    Raets, M M A; Dudink, J; Govaert, P

    2015-01-01

    The germinal matrix (GM) is a richly vascularized, transient layer near the ventricles. It produces neurons and glial cells, and is present in the foetal brain between 8 and 36 weeks of gestation. At 25 weeks, it reaches its maximum volume and subsequently withers. The GM is vulnerable to haemorrhag

  5. Effect of multilayer structure, stacking order and external electric field on the electrical properties of few-layer boron-phosphide.

    Science.gov (United States)

    Chen, Xianping; Tan, Chunjian; Yang, Qun; Meng, Ruishen; Liang, Qiuhua; Jiang, Junke; Sun, Xiang; Yang, D Q; Ren, Tianling

    2016-06-28

    Development of nanoelectronics requires two-dimensional (2D) systems with both direct-bandgap and tunable electronic properties as they act in response to the external electric field (E-field). Here, we present a detailed theoretical investigation to predict the effect of atomic structure, stacking order and external electric field on the electrical properties of few-layer boron-phosphide (BP). We demonstrate that the splitting of bands and bandgap of BP depends on the number of layers and the stacking order. The values for the bandgap show a monotonically decreasing relationship with increasing layer number. We also show that AB-stacking BP has a direct-bandgap, while ABA-stacking BP has an indirect-bandgap when the number of layers n > 2. In addition, for a bilayer and a trilayer, the bandgap increases (decreases) as the electric field increases along the positive direction of the external electric field (E-field) (negative direction). In the case of four-layer BP, the bandgap exhibits a nonlinearly decreasing behavior as the increase in the electric field is independent of the electric field direction. The tunable mechanism of the bandgap can be attributed to a giant Stark effect. Interestingly, the investigation also shows that a semiconductor-to-metal transition may occur for the four-layer case or more layers beyond the critical electric field. Our findings may inspire more efforts in fabricating new nanoelectronics devices based on few-layer BP.

  6. Developmental analysis of the external granular layer in the meander tail mutant mouse: do cerebellar microneurons have independent progenitors?

    Science.gov (United States)

    Napieralski, J A; Eisenman, L M

    1993-08-01

    The cerebellum of the meander tail mutant mouse (mea/mea) is characterized by an apparently normal cytoarchitecture posteriorly with an abrupt transition to an abnormal anterior region. Anteriorly, there is abnormal foliation, a drastic reduction in the granule cells (GC) population, disorganization of the Purkinje cells (PC), and a virtual absence of Bergmann glial processes. In this paper we analyze the prenatal and postnatal development of the cerebellum in the mea/mea and attempt to determine the phenotypic onset of the mutation in the anterior region. Hematoxylin and eosin stained sections reveal a morphological difference in the cerebellum of the mea/mea as early as embryonic day 16 characterized by a reduction in the external granule cell layer (EGL). The reduction in the EGL becomes increasingly apparent as development proceeds. This deficit in the EGL most probably results in the absence of GC, but it is unclear at this point whether reduced migration, proliferation, and/or increased cell death is the major factor. Interestingly, immunohistochemical staining with a monoclonal antibody against parvalbumin reveals that the basket and stellate cells, which are also thought to arise from the EGL, are present in the anterior region of the mea/mea cerebellum. These results suggest that the lack of GC in the meander tail is due to an early expressed abnormality of the EGL. However, the presence of the basket and/or stellate cells raises some interesting questions concerning the lineage of the cerebellar microneurons.

  7. Simulation studies on the effect of a buffer layer on the external parameters of hydrogenated amorphous silicon –– solar cells

    Indian Academy of Sciences (India)

    K Rajeev Kumar; M Zeman

    2008-10-01

    Device modeling of –– junction amorphous silicon solar cells has been carried out using the amorphous semiconductor analysis (ASA) simulation programme. The aim of the study was to explain the role of a buffer layer in between the - and -layers of the –– solar cell on the external parameters such as dark current density and open circuit voltage. Investigations based on the simulation of dark – characteristics revealed that as the buffer layer thickness increases the dark current for a given voltage decreases.

  8. Germination induction of dormant Avena fatua caryopses by KAR(1) and GA(3) involving the control of reactive oxygen species (H2O2 and O2(·-)) and enzymatic antioxidants (superoxide dismutase and catalase) both in the embryo and the aleurone layers.

    Science.gov (United States)

    Cembrowska-Lech, Danuta; Koprowski, Marek; Kępczyński, Jan

    2015-03-15

    Avena fatua L. caryopses did not germinate at 20 °C in darkness because they were dormant. However, they were able to germinate in the presence of karrikinolide (KAR1), a key bioactive compound present in smoke, and also in the presence of gibberellin A3 (GA3), a commonly known stimulator of seed germination. The aim of this study was to collect information on a possible relationship between the above regulators and abscisic acid (ABA), reactive oxygen species (ROS) and ROS scavenging antioxidants in the regulation of dormant caryopses germination. KAR1 and GA3 caused complete germination of dormant A. fatua caryopses. Hydrogen peroxide (H2O2), compounds generating the superoxide (O2(·-)), i.e. menadione (MN), methylviologen (MV) and an inhibitor of catalase activity, aminotriazole (AT), induced germination of dormant caryopses. KAR1, GA3, H2O2 and AT decreased ABA content in embryos. Furthermore, KAR1, GA3, H2O2, MN, MV and AT increased α-amylase activity in caryopses. The effect of KAR1 and GA3 on ROS (H2O2, O2(·-)) and activities of the superoxide dismutase (SOD) and catalase (CAT) were determined in caryopses, embryos and aleurone layers. SOD was represented by four isoforms and catalase by one. In situ localization of ROS showed that the effect of KAR1 and GA3 was associated with the localization of hydrogen peroxide mainly on the coleorhiza. However, the superoxide was mainly localized on the surface of the scutellum. Superoxide was also detected in the protruding radicle. Germination induction of dormant caryopses by KAR1 and GA3 was related to an increasing content of H2O2, O2(·-)and activities of SOD and CAT in embryos, thus ROS homeostasis was probably required for the germination of dormant caryopses. The above regulators increased the content of ROS in aleurone layers and decreased the activities of SOD and CAT, probably leading to the programmed cell death. The presented data provide new insights into the germination induction of A. fatua dormant

  9. Phosphorescent OLEDs: Sky-Blue Phosphorescent OLEDs with 34.1% External Quantum Efficiency Using a Low Refractive Index Electron Transporting Layer (Adv. Mater. 24/2016).

    Science.gov (United States)

    Shin, Hyun; Lee, Jeong-Hwan; Moon, Chang-Ki; Huh, Jin-Suk; Sim, Bomi; Kim, Jang-Joo

    2016-06-01

    J.-J. Kim and co-workers achieve highly efficient blue organic light-emitting diodes (OLEDs) using a low-refractive-index layer. As described on page 4920, an external quantum efficiency over 34% is achieved, owing to the low refractive index of the materials. A milepost and a shining entrance of the castle are the metaphor indicating the way to highly efficient blue OLEDs. On the way to the castle, the depicted chemical structures serve as the light-emitting layer. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Hydrogenic impurity, external electric and magnetic fields effects on the nonlinear optical properties of a multi-layer spherical quantum dot

    Science.gov (United States)

    Tanhaei, M. H.; Rezaei, G.

    2016-10-01

    In this work, effects of an on-center hydrogenic impurity, external electric and magnetic fields on the optical rectification coefficient (ORC), second and third harmonic generations (SHG and THG) of a multi-layer spherical quantum dot (MLSQD) are studied. Energy eigenvalues and eigenvectors are calculated using the direct matrix diagonalization method and optical properties are obtained using the compact density matrix approach. Our results reveal that the hydrogenic impurity and external fields have a great influence on these optical quantities. Hydrogenic impurity reduces the magnitude of the resonant peaks and shifts them to the higher energies. An increase in the magnetic (electric) field, leads to increase (decrease) the interval energies and the dipole moment matrix elements. Therefore, resonant peaks of these optical quantities find an obvious blue (red) shift and their magnitudes enhance (diminish) with increasing the external magnetic (electric) field.

  11. Neonatal disorders of germinal matrix.

    Science.gov (United States)

    Raets, M M A; Dudink, J; Govaert, P

    2015-11-01

    The germinal matrix (GM) is a richly vascularized, transient layer near the ventricles. It produces neurons and glial cells, and is present in the foetal brain between 8 and 36 weeks of gestation. At 25 weeks, it reaches its maximum volume and subsequently withers. The GM is vulnerable to haemorrhage in preterm infants. This selective vulnerability is explained by limited astrocyte end-feet coverage of microvessels, reduced expression of fibronectin and immature tight junctions. Focal lesions in the neonatal period include haemorrhage, germinolysis and stroke. Such lesions in transient layers interrupt normal brain maturation and induce neurodevelopmental sequelae.

  12. Effects of stacking order, layer number and external electric field on electronic structures of few-layer C2N-h2D.

    Science.gov (United States)

    Zhang, Ruiqi; Li, Bin; Yang, Jinlong

    2015-09-07

    Recently, a new type of two-dimensional layered material, i.e. a nitrogenated holey two-dimensional structure C2N-h2D, has been synthesized using a simple wet-chemical reaction and used to fabricate a field-effect transistor device (Nat. Commun., 2015, 6, 6486). Here we have performed a first-principles study of the electronic properties of few-layer C2N-h2D with different stacking orders and layer numbers. Because of the interlayer coupling mainly in terms of the orbital interaction, band structure of this system, especially splitting of the bands and band gap, depends on its stacking order between the layers, and the band gap exhibits monotonically decreasing behavior as the layer number increases. All the few-layer C2N-h2D materials have characteristics of direct band gap, irrespective of the stacking order and layer number examined in our calculations. And bulk C2N-h2D has an indirect or direct band gap, depending on the stacking order. Besides, when we apply an out-of-plane electric field on few-layer C2N-h2D, its band gap will decrease as the electric field increases due to a giant Stark effect except for the monolayer case, and even a semiconductor-to-metal transition may occur for few-layer C2N-h2D with more layers under an appropriate electric field. Owing to their tunable band gaps in a wide range, the layered C2N-h2D materials will have tremendous opportunities to be applied in nanoscale electronic and optoelectronic devices.

  13. Smoke-induced seed germination in California chaparral

    Science.gov (United States)

    Keeley, J.E.; Fotheringham, C.J.

    1998-01-01

    The California chaparral community has a rich flora of species with different mechanisms for cuing germination to postfire conditions. Heat shock triggers germination of certain species but has no stimulatory effect on a great many other postfire species that are chemically stimulated by combustion products. Previous reports have shown that charred wood will induce germination, and here we report that smoke also induces germination in these same species. Smoke is highly effective, often inducing 100% germination in deeply dormant seed populations with 0% control germination. Smoke induces germination both directly and indirectly by aqueous or gaseous transfer from soil to seeds. Neither nitrate nor ammonium ions were effective in stimulating germination of smoke-stimulated species, nor were most of the quantitatively important gases generated by biomass smoke. Nitrogen dioxide, however, was very effective at inducing germination in Caulanthus heterophyllus (Brassicaceae), Emmenanthe penduliflora (Hydrophyllaceae), Phacelia grandiflora (Hydrophyllaceae), and Silene multinervia (Caryophyllaceae). Three species, Dendromecon rigida (Papaveraceae), Dicentra chrysantha, and Trichostema lanatum (Lamiaceae), failed to germinate unless smoke treatment was coupled with prior treatment of 1 yr soil storage. Smoke-stimulated germination was found in 25 chaparral species, representing 11 families, none of which were families known for heat-shock-stimulated germination. Seeds of smoke-stimulated species have many analogous characteristics that separate them from most heat-shock-stimulated seeds, including: (1) outer seed coats that are highly textured, (2) a poorly developed outer cuticle, (3) absence of a dense palisade tissue in the seed coat, and (4) a subdermal membrane that is semipermeable, allowing water passage but blocking entry of large (molecular mass > 500) solutes. Tentative evidence suggests that permeability characteristics of this subdermal layer are altered by

  14. Thickness optimization of the ZnO based TCO layer in a CZTSSe solar cell. Evolution of its performance with thickness when external temperature changes.

    Science.gov (United States)

    Chadel, Meriem; Moustafa Bouzaki, Mohammed; Chadel, Asma; Aillerie, Michel; Benyoucef, Boumediene

    2017-07-01

    The influence of the thickness of a Zinc Oxide (ZnO) transparent conductive oxide (TCO) layer on the performance of the CZTSSe solar cell is shown in detail. In a photovoltaic cell, the thickness of each layer largely influence the performance of the solar cell and optimization of each layer constitutes a complete work. Here, using the Solar Cell Capacitance Simulation (SCAPS) software, we present simulation results obtained in the analyze of the influence of the TCO layer thickness on the performance of a CZTSSe solar cell, starting from performance of a CZTSSe solar cell commercialized in 2014 with an initial efficiency equal to 12.6%. In simulation, the temperature was considered as a functioning parameter and the evolution of tthe performance of the cell for various thickness of the TCO layer when the external temperature changes is simulated and discussed. The best efficiency of the solar cell based in CZTSSe is obtained with a ZnO thickness equal to 50 nm and low temperature. Based on the considered marketed cell, we show a technological possible increase of the global efficiency achieving 13% by optimization of ZnO based TCO layer.

  15. [Malignant germinal tumours of the mediastinum: diagnosis and treatment].

    Science.gov (United States)

    Lemarié, E

    2004-11-01

    Mediastinal germinal tumours are composed of tissues resembling those that follow one another during embryo development, by differentiation of the primordial and extraembryonic layers. Such practice separates the mature teratomas (benign), seminomas and non-seminomatous germinal tumours (NSGT). Platin-based chemotherapy has shattered the prognosis of such tumours.

  16. Seed germination and vigor.

    Science.gov (United States)

    Rajjou, Loïc; Duval, Manuel; Gallardo, Karine; Catusse, Julie; Bally, Julia; Job, Claudette; Job, Dominique

    2012-01-01

    Germination vigor is driven by the ability of the plant embryo, embedded within the seed, to resume its metabolic activity in a coordinated and sequential manner. Studies using "-omics" approaches support the finding that a main contributor of seed germination success is the quality of the messenger RNAs stored during embryo maturation on the mother plant. In addition, proteostasis and DNA integrity play a major role in the germination phenotype. Because of its pivotal role in cell metabolism and its close relationships with hormone signaling pathways regulating seed germination, the sulfur amino acid metabolism pathway represents a key biochemical determinant of the commitment of the seed to initiate its development toward germination. This review highlights that germination vigor depends on multiple biochemical and molecular variables. Their characterization is expected to deliver new markers of seed quality that can be used in breeding programs and/or in biotechnological approaches to improve crop yields.

  17. The stability of two layer dielectric-electrolyte micro-flow subjected to an external electric field

    Science.gov (United States)

    Demekhin, E. A.; Ganchenko, G. S.; Navarkar, A.; Amiroudine, S.

    2016-09-01

    The two-phase microflow of conductive (electrolyte) and non-conductive (dielectric) viscous liquids bounded by two solid walls in an external electric field is scrutinized. The lower solid wall, which is adjoined to the electrolyte, is a charged dielectric surface; the upper wall which bounds the dielectric is insulated. The problem has a steady one-dimensional (1D) solution. The theoretical results for a plug-like velocity profile are successfully compared with available theoretical and experimental data from the literature. The linear stability of the steady-state flow is investigated numerically with spectral Galerkin's method for solving linearized eigenvalue problem. This method was successfully applied for related problem of electroosmosis of ultrathin film. The numerical analysis provides insights on the coexistence of long and short-wave instabilities. The influence of control parameters such as the ratio of the viscosities of both liquids and the ratio of the channel heights on the stability of one-dimensional flow was investigated for different values of external electric field. The influence of an external pressure gradient on the flow stability is also investigated. The experimental facts established by other authors, according to which the system destabilizes if the electroosmotic flow is oppositely directed to the external pressure gradient, is confirmed in this work. Otherwise stabilization takes place.

  18. Control of boundary layer transition location and plate vibration in the presence of an external acoustic field

    Science.gov (United States)

    Maestrello, L.; Grosveld, F. W.

    1991-01-01

    The experiment is aimed at controlling the boundary layer transition location and the plate vibration when excited by a flow and an upstream sound source. Sound has been found to affect the flow at the leading edge and the response of a flexible plate in a boundary layer. Because the sound induces early transition, the panel vibration is acoustically coupled to the turbulent boundary layer by the upstream radiation. Localized surface heating at the leading edge delays the transition location downstream of the flexible plate. The response of the plate excited by a turbulent boundary layer (without sound) shows that the plate is forced to vibrate at different frequencies and with different amplitudes as the flow velocity changes indicating that the plate is driven by the convective waves of the boundary layer. The acoustic disturbances induced by the upstream sound dominate the response of the plate when the boundary layer is either turbulent or laminar. Active vibration control was used to reduce the sound induced displacement amplitude of the plate.

  19. The biomechanics of seed germination.

    Science.gov (United States)

    Steinbrecher, Tina; Leubner-Metzger, Gerhard

    2016-12-07

    From a biomechanical perspective, the completion of seed (and fruit) germination depends on the balance of two opposing forces: the growth potential of the embryonic axis (radicle-hypocotyl growth zone) and the restraint of the seed-covering layers (endosperm, testa, and pericarp). The diverse seed tissues are composite materials which differ in their dynamic properties based on their distinct cell wall composition and water uptake capacities. The biomechanics of embryo cell growth during seed germination depend on irreversible cell wall loosening followed by water uptake due to the decreasing turgor, and this leads to embryo elongation and eventually radicle emergence. Endosperm weakening as a prerequisite for radicle emergence is a widespread phenomenon among angiosperms. Research into the biochemistry and biomechanics of endosperm weakening has demonstrated that the reduction in puncture force of a seed's micropylar endosperm is environmentally and hormonally regulated and involves tissue-specific expression of cell wall remodelling proteins such as expansins, diverse hydrolases, and the production of directly acting apoplastic reactive oxygen. The endosperm-weakening biomechanics and its underlying cell wall biochemistry differ between the micropylar (ME) and chalazal (CE) endosperm domains. In the ME, they involve cell wall loosening, cell separation, and programmed cell death to provide decreased and localized ME tissue resistance, autolysis, and finally the formation of an ME hole required for radicle emergence. Future work will further unravel the molecular mechanisms, environmental regulation, and evolution of the diverse biomechanical cell wall changes underpinning the control of germination by endosperm weakening.

  20. [Research advance in seed germination of desert woody plants].

    Science.gov (United States)

    Chang, Wei; Wu, Jian-guo; Liu, Yan-hong

    2007-02-01

    This paper reviewed the research methods of desert woody plants seed germination, and the effects of internal and external ecological factors on it. Most researchers use incubator and artificial climate chamber to dispose the seeds, while field investigation was few involved. Seed dormancy is the important physiological factor affecting germination, while seed size, mass and color are closely correlated with its maturity and vigor. The poor permeability of seed capsule is a barrier that restrains the germination, which can be weakened or eliminated by shaving, cutting, treating with low temperature, and dipping in chemical reagent, etc. Seed water content has a close correlation with its storage life and water-absorbing capability. Suitable temperature is the prerequisite of seed germination, while changing temperature can accelerate the germination. Soil moisture content is a limiting factor, while illumination is not so essential to the seed germination of most desert woody plants. Sand-burying plays an important role in the seed germination through regulating illumination, temperature, and soil moisture content. Salinity stress restrains the seed germination of desert woody plants observably. In further studies, the effects of multi-factors and the eco-physiological and molecular biological mechanisms of germination should be more concerned.

  1. The multi-layered ring under parabolic distribution of radial stresses combined with uniform internal and external pressure

    Directory of Open Access Journals (Sweden)

    Christos F. Markides

    2017-04-01

    Full Text Available A recently introduced solution for the stress- and displacement-fields, developed in a multi-layered circular ring, composed of a finite number of linearly elastic concentric layers, subjected to a parabolic distribution of ra-dial stresses, is here extended to encompass a more general loading scheme, closer to actual conditions. The loading scheme includes, besides the para¬-bolic radial stresses, a combination of uniform pressures acting along the outer- and inner- most boundaries of the layered ring. The analytic solution of the problem is achieved by adopting Savin’s pioneering approach for an infinite plate with a hole strengthened by rings. Taking advantage of the results provided by the ana¬lytic solution, a numerical model, simulating the configuration of a three-layered ring (quite commonly encountered in practic¬al applications is validated. The numerical model is then used for a parametric analysis enlightening some crucial aspects of the overall response of the ring.

  2. 外界条件对4个安祖花品种花粉萌发及生长的影响%Effect of External Condition to the Pollen Germination and Growth of Four Anthurium andraeanum Varieties

    Institute of Scientific and Technical Information of China (English)

    康黎芳; 曹冬梅; 温喜珍; 张超; 段九菊; 王云山

    2012-01-01

    This paper studied the optimum culture medium formula and acquisition time for pollen germination of four Anthurium andraeanum varieties including Fire, Mississippi, Success and Artus, and the pollen germination rates under the light and dark condition through vitro germination method. The results showed: the best culture medium formula of Fire, Mississippi and Artus were sucrose 5% + boric acid 10 μL/mL, pH 6.0; the best culture medium formula of Success was sucrose 5% + boric acid 25 μL/mL, pH 6.5. The order of the pollen germination rate for four Anthurium andraeanum varieties under the optimum culture condition as follows: Mississippi, Success, Fire and Artus; The best acquisition time of pollen was at 16:00 for four Anthurium andraeanum varieties and at this time, their pollen germination rates were the highest. Pollen germination rates of four Anthurium andraeanum varieties were higher under the light conditions, and malformation rates vice versa. The rate of pollen tube growth of Fire was the quickest.%通过体外萌发的方法,研究了火焰、密西西比、成功、火鹤4种安祖花花粉萌发的最佳培养基配方、花粉的最佳采集时间以及光暗条件对安祖花花粉萌发率的影响.结果表明,火焰、密西西比和火鹤花粉萌发的最佳培养基配方为:蔗糖5%+硼酸10μL/mL,pH值为6.0;成功花粉萌发的最佳培养基配方为:蔗糖5%+硼酸25μL/mL,pH值为6.5.在最适培养条件下,4种安祖花花粉萌发率由高到低依次为密西西比>成功>火焰>火鹤;不同品种的安祖花均在16:00采集的花粉萌发率最高;4种安祖花的花粉均在光照条件下萌发率高,畸形率则相反,大多数品种的花粉在黑暗条件下萌发时会形成更高比例的畸形花粉;花粉管生长速率以火焰最大.

  3. The permeability of SPION over an artificial three-layer membrane is enhanced by external magnetic field

    Directory of Open Access Journals (Sweden)

    Ge Xianxi

    2006-04-01

    Full Text Available Abstract Background Sensorineural hearing loss, a subset of all clinical hearing loss, may be correctable through the use of gene therapy. We are testing a delivery system of therapeutics through a 3 cell-layer round window membrane model (RWM model that may provide an entry of drugs or genes to the inner ear. We designed an in vitro RWM model similar to the RWM (will be referred to throughout the paper as RWM model to determine the feasibility of using superparamagnetic iron oxide (Fe3O4 nanoparticles (SPION for targeted delivery of therapeutics to the inner ear. The RWM model is a 3 cell-layer model with epithelial cells cultured on both sides of a small intestinal submucosal (SIS matrix and fibroblasts seeded in between. Dextran encapsulated nanoparticle clusters 130 nm in diameter were pulled through the RWM model using permanent magnets with flux density 0.410 Tesla at the pole face. The SIS membranes were harvested at day 7 and then fixed in 4% paraformaldehyde. Transmission electron microscopy and fluorescence spectrophotometry were used to verify transepithelial transport of the SPION across the cell-culture model. Histological sections were examined for evidence of SPION toxicity, as well to generate a timeline of the position of the SPION at different times. SPION also were added to cells in culture to assess in vitro toxicity. Results Transepithelial electrical resistance measurements confirmed epithelial confluence, as SPION crossed a membrane consisting of three co-cultured layers of cells, under the influence of a magnetic field. Micrographs showed SPION distributed throughout the membrane model, in between cell layers, and sometimes on the surface of cells. TEM verified that the SPION were pulled through the membrane into the culture well below. Fluorescence spectrophotometry quantified the number of SPION that went through the SIS membrane. SPION showed no toxicity to cells in culture. Conclusion A three-cell layer model of the

  4. The Python user interface of the elsA cfd software: a coupling framework for external steering layers

    CERN Document Server

    Marc, Lazareff

    2016-01-01

    The Python--elsA user interface of the elsA CFD (Computational Fluid Dynamics) software has been developed to allow users to specify simulations with confidence, through a global context of description objects grouped inside scripts. The software main features are generated documentation, context checking and completion, and helpful error management. Further developments have used this foundation as a coupling framework, allowing (thanks to the descriptive approach) the coupling of external algorithms with the CFD solver in a rather simple and abstract way, leading to more success in complex simulations. Along with the description of the technical part of the interface, we try to gather the salient points pertaining to the psychological viewpoint of user experience (UX).

  5. Buckling delamination of the circular sandwich plate with piezoelectric face and elastic core layers under rotationally symmetric external pressure

    Science.gov (United States)

    Akbarov, Surkay D.; Cafarova, Fazile I.; Yahnioglu, Nazmiye

    2017-02-01

    The axisymmetric buckling delamination of the piezoelectric circular sandwich plate with piezoelectric face and elastic (metal) core layers around the interface penny-shaped cracks is investigated. The case is considered where short-circuit conditions with respect to the electrical potential on the upper and lower and also lateral surfaces of face layers are satisfied. It is assumed that the edge surfaces of the cracks have an infinitesimal rotationally symmetric initial imperfection and the development of this imperfection with rotationally symmetric compressive forces acting on the lateral surface of the plate is studied by employing the exact geometrically non-linear field equations and relations of electro-elasticity for piezoelectric materials. Solution to the considered nonlinear problem is reduced to solution of the series boundary value problems derived by applying the linearization procedure with respect to small imperfection of the sought values. Numerical results reveal the effect of piezoelectricity as well as geometrical and material parameters on the critical values are determined numerically by employing finite element method (FEM).

  6. Application of the model of the printed circuit board with regard to the topology of external conductive layers for calculation of the thermal conditions of the printed circuit board

    Science.gov (United States)

    Rybakov, I. M.; Goryachev, N. V.; Kochegarov, I. I.; Grishko, A. K.; Brostilov, S. A.; Yurkov, N. K.

    2017-01-01

    The paper proves the necessity of taking into account external conductive layers of the printed circuit board with the thermal physical designing radio-electronic means. For example, a single printed circuit board shows the level of influence of the external conductive layer on the thermal conditions of the printed circuit board. It proved the influence of Joule heat in the thermal conditions of a single conductor. Developed geometrical and thermal printed circuit board models take into account the topological layer and can improve the accuracy of determining the thermal conditions of the printed circuit board.

  7. Involvement of Coat Proteins in Bacillus subtilis Spore Germination in High-Salinity Environments.

    Science.gov (United States)

    Nagler, Katja; Setlow, Peter; Reineke, Kai; Driks, Adam; Moeller, Ralf

    2015-10-01

    The germination of spore-forming bacteria in high-salinity environments is of applied interest for food microbiology and soil ecology. It has previously been shown that high salt concentrations detrimentally affect Bacillus subtilis spore germination, rendering this process slower and less efficient. The mechanistic details of these salt effects, however, remained obscure. Since initiation of nutrient germination first requires germinant passage through the spores' protective integuments, the aim of this study was to elucidate the role of the proteinaceous spore coat in germination in high-salinity environments. Spores lacking major layers of the coat due to chemical decoating or mutation germinated much worse in the presence of NaCl than untreated wild-type spores at comparable salinities. However, the absence of the crust, the absence of some individual nonmorphogenetic proteins, and the absence of either CwlJ or SleB had no or little effect on germination in high-salinity environments. Although the germination of spores lacking GerP (which is assumed to facilitate germinant flow through the coat) was generally less efficient than the germination of wild-type spores, the presence of up to 2.4 M NaCl enhanced the germination of these mutant spores. Interestingly, nutrient-independent germination by high pressure was also inhibited by NaCl. Taken together, these results suggest that (i) the coat has a protective function during germination in high-salinity environments; (ii) germination inhibition by NaCl is probably not exerted at the level of cortex hydrolysis, germinant accessibility, or germinant-receptor binding; and (iii) the most likely germination processes to be inhibited by NaCl are ion, Ca(2+)-dipicolinic acid, and water fluxes.

  8. A subpial, transitory germinal zone forms chains of neuronal precursors in the rabbit cerebellum.

    Science.gov (United States)

    Ponti, Giovanna; Peretto, Paolo; Bonfanti, Luca

    2006-06-01

    Protracted neurogenesis occurs at different postnatal stages in different brain locations, whereby leading to site-specific adult neurogenesis in some cases. No spontaneous genesis of neurons occurs in the cerebellum after the postnatal genesis of granule cells from the external germinal layer (EGL), a transitory actively proliferating zone which is thought to be exhausted before puberty. Here, we show the protracted genesis of newly generated neuronal precursors in the cerebellar cortex of young rabbits, persisting beyond puberty. Neuroblasts generated within an actively proliferating subpial layer thus extending the postnatal EGL are arranged to form thousands of tangential chains reminiscent of those responsible for cell migration in the forebrain subventricular zone. These subpial chains cover the whole cerebellar surface from the 2nd to the 5th month of life, then disappearing after puberty. In addition, we describe the appearance of similar groups of cells at the end of granule cell genesis in the mouse cerebellum, here limited to the short period of EGL exhaustion (4-5 days). These results show common features do exist in the postnatal reorganization of secondary germinal layers of brain and cerebellum at specific stages, parallel to differences in the slowing down of cerebellar neurogenesis among mammalian species.

  9. The inner perivitelline layer sperm-hole assay: use of filter paper rings for the isolation of the perivitelline layer overlying the germinal disc and new observations on its morphology

    Science.gov (United States)

    Sperm must penetrate the hen’s ovum (egg yolk) for fertilization. The inner perivitelline layer (IPL) is a fibrous protein mesh surrounding the ovum that the sperm attach to and then digest a hole through at the onset of the fertilization process. This process of sperm attachment and digestion of ...

  10. Effects of UV-irradiation on seed germination.

    Science.gov (United States)

    Noble, Rudolf E

    2002-11-01

    The advent of depletion of the ozone layer with the reported subsequent increase of UV-irradiation has led to heightened interest in the effects of UV light on cellular organisms. In this study, the effects of UV-irradiation was studied on the germination of kale, cabbage, radish and agave seeds. In all cases, UV light sped the germination of these seeds but the subsequent growth of the seedlings was markedly retarded. Pictures, taken at day 15, are presented to show this latter effect and the possible effects of UV-irradiation on seed germination are discussed.

  11. Hydrolysis of cortex peptidoglycan during bacterial spore germination.

    Science.gov (United States)

    Makino, Shio; Moriyama, Ryuichi

    2002-06-01

    Despite the most extreme dormancy and resistance properties among living systems, bacterial endospores retain an alert sensory mechanism to respond to the germinants and initiate germination. Although the molecular mechanism of the germination process is not completely described, current progress in the studies on the enzymes involved in the process gave us a somewhat clearer picture of the process of spore peptidoglycan (cortex) hydrolysis, a major biochemical event in germination. Germination-specific cortex-lytic enzymes require muramic acid d-lactam in their substrates. At least two types of enzymes are involved in the germination process: a spore cortex-lytic enzyme (SCLE) and a cortical fragment-lytic enzyme (CFLE). Except for their peptidoglycan-binding regions, the primary structures of SCLE and CFLE vary according species. Both enzymes differ in their hydrolytic bond-specificities and recognition of the substrates morphology. SCLE appears to initiate germination by uncrosslinking the intract cortex, and the CFLE further degrades the polysaccharide moiety of the SCLE-modified cortex. In vivo CFLE activity is likely regulated by its requirement for partially un-crosslinked cortex, while SCLE requires activation process. Clostridium perfringens SCLE is activated by a germination-specific serine protease during germination, but the activation mechanism of SCLE in Bacillus species is unknown. Cortex-lytic enzymes are expressed at the early stage of sporulation but the compartment of expression depends on proteins. However, all enzymes are located outside the cortex layer in dormant spores, suggesting that the hydrolysis process initiates at the exterior side of the cortex. The assembly of the germination apparatus is also discussed.

  12. Modulation of Anti-Oxidation Ability by Proanthocyanidins during Germination of Arabidopsis thaliana Seeds

    Institute of Scientific and Technical Information of China (English)

    Li-Guo Jia; Zi-Wei Sheng; Wei-Feng Xu; Ying-Xuan Li; Ying-Gao Liu; Yi-Ji Xia; Jian-Hua Zhang

    2012-01-01

    Proanthocyanidins (PAs) as the end products of flavonoid biosynthetic pathway mainly accumulate in seed coat but their biological function is largely unknown.We studied the anti-oxidation ability in seed coat and germination changes under externally applied oxidative stresses in PAs-deficient mutants of Arabidopsis.Germination of PAs-deficient mutant seeds was faster than that of wild-type under low or no oxidative stress,suggesting a PAs-induced inhibition of germination.When the applied oxidative stress was high,germination of PAs-deficient mutants was lower than that of wild-type,suggesting a loss of PAs-related anti-oxidation ability in the mutants.Using ABA signaling mutants,our studies demonstrated that both ABA signaling pathway and PAs were important for the response to serve oxidative stress during seed germination.However,the discrepancy of the response between abi mutants and PAs mutants to oxidative stress suggests that ABA signaling pathway may not play a major role in PAs' action in alleviating oxidative stress.Under low or no oxidative stress,germination was mainly determined by the ABA content in seed and the PAs-deficient mutant seeds germinated faster due to their lower ABA content than wild-type.However,oxidative injury inhibited germination when PAs-deficient seeds germinated under high oxidative stress.Wild-type exhibited higher germination under the high oxidative stress due to the PAs' anti-oxidation ability.Oxidative stress applied externally led to changes in endogenous PAs contents that coincided with the expression changes of PAs biogenesis genes.PAs modulated the activities of some key enzymes that controlled the levels of reactive oxygen species and the anti-oxidation capacity during the seed germination.This work suggests that PAs contribute to the adaptive mechanism that helps germination under environmental stresses by playing dual roles in both germination control and anti-oxidation reaction.

  13. Modulation of anti-oxidation ability by proanthocyanidins during germination of Arabidopsis thaliana seeds.

    Science.gov (United States)

    Jia, Li-Guo; Sheng, Zi-Wei; Xu, Wei-Feng; Li, Ying-Xuan; Liu, Ying-Gao; Xia, Yi-Ji; Zhang, Jian-Hua

    2012-03-01

    Proanthocyanidins (PAs) as the end products of flavonoid biosynthetic pathway mainly accumulate in seed coat but their biological function is largely unknown. We studied the anti-oxidation ability in seed coat and germination changes under externally applied oxidative stresses in PAs-deficient mutants of Arabidopsis. Germination of PAs-deficient mutant seeds was faster than that of wild-type under low or no oxidative stress, suggesting a PAs-induced inhibition of germination. When the applied oxidative stress was high, germination of PAs-deficient mutants was lower than that of wild-type, suggesting a loss of PAs-related anti-oxidation ability in the mutants. Using ABA signaling mutants, our studies demonstrated that both ABA signaling pathway and PAs were important for the response to serve oxidative stress during seed germination. However, the discrepancy of the response between abi mutants and PAs mutants to oxidative stress suggests that ABA signaling pathway may not play a major role in PAs' action in alleviating oxidative stress. Under low or no oxidative stress, germination was mainly determined by the ABA content in seed and the PAs-deficient mutant seeds germinated faster due to their lower ABA content than wild-type. However, oxidative injury inhibited germination when PAs-deficient seeds germinated under high oxidative stress. Wild-type exhibited higher germination under the high oxidative stress due to the PAs' anti-oxidation ability. Oxidative stress applied externally led to changes in endogenous PAs contents that coincided with the expression changes of PAs biogenesis genes. PAs modulated the activities of some key enzymes that controlled the levels of reactive oxygen species and the anti-oxidation capacity during the seed germination. This work suggests that PAs contribute to the adaptive mechanism that helps germination under environmental stresses by playing dual roles in both germination control and anti-oxidation reaction.

  14. Restricted access molecularly imprinted polymers obtained by bovine serum albumin and/or hydrophilic monomers' external layers: a comparison related to physical and chemical properties.

    Science.gov (United States)

    Santos, Mariane Gonçalves; Moraes, Gabriel de Oliveira Isac; Nakamura, Maurício Gustavo; dos Santos-Neto, Álvaro José; Figueiredo, Eduardo Costa

    2015-11-21

    Molecularly imprinting polymers (MIPs) can be modified with external layers in order to obtain restricted access molecularly imprinted polymers (RAMIPs) able to exclude macromolecules and retain low weight compounds. These modifications have been frequently achieved using hydrophilic monomers, chemically bound on the MIP surface. Recently, our group proposed a new biocompatible RAMIP based on the formation of a bovine serum albumin coating on the surface of MIP particles. This material has been used to extract drugs directly from untreated human plasma samples, but its physicochemical evaluation has not been carried out yet, mainly in comparison with RAMIPs obtained by hydrophilic monomers. Thus, we proposed in this paper a comparative study involving the surface composition, microscopic aspect, selectivity, binding kinetics, adsorption and macromolecule elimination ability of these different materials. We concluded that the synthesis procedure influences the size and shape of particles and that hydrophilic co-monomer addition as well as coating with BSA do not alter the chemical recognition ability of the material. The difference between imprinted and non-imprinted polymers' adsorption was evident (suggesting that imprinted polymers have a better capacity to bind the template than the non-imprinted ones). The Langmuir model presents the best fit to describe the materials' adsorption profile. The polymer covered with hydrophilic monomers presented the best adsorption for the template in an aqueous medium, probably due to a hydrophilic layer on its surface. We also concluded that an association of the hydrophilic monomers with the bovine serum albumin coating is important to obtain materials with higher capacity of macromolecule exclusion.

  15. Biochemical Changes Associated with Germinating Rice Grains and Germination Improvement

    Institute of Scientific and Technical Information of China (English)

    Subajiny VELUPPILLAI; Ketheeswary NITHYANANTHARAJAH; Seevaratnam VASANTHARUBA; Sandrasegarampillai BALAKUMAR; Vasanthy ARASARATNAM

    2009-01-01

    To determine biochemical changes during the germination of rice grains (Oryza sativa L. subsp. indica var. Mottaikaruppan) and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfate (SDS) (1.0 g/L) and Triton-X-100 (1.0 mL/L)], whole rice grains soaked in distilled water for 12 h at 30oC were germinated in the dark at 30oC for five days. The highest germination rate (77.1%) was obtained on the 5th day. An increase in the content of reducing sugars from 7.3 to 58.1 mg/g DM (dry matter) was observed from the 1st day of germination. Free amino acids and soluble protein contents increased to 3.69 and 5.29 mg/g DM, respectively on the 5th day of germination. Total protein content decreased from 100.5 to 91.0 g/kg DM during germination. Increases in amylolytic (1.1 to 190.0 U/g DM) and proteolytic (0 to 0.12 U/g DM) activities were observed during germination. Effects of different concentrations of gibberellic acid on the germination of rice grains were evaluated and 0.1 g/L was found to promote germination. When effects of gibberellic acid (0.1 g/L) and surfactants were evaluated individually and together, higher germination rate was observed in the control experiment (grains germinated in distilled water), whereas giberellic acid and surfactants decreased the germination rate. Therefore, the flour obtained from the grains germinated for four days using distilled water to obtain high content of soluble materials and enzyme activities can be used in preparation of bakery items.

  16. The SH2 domain-containing 5-phosphatase SHIP2 is expressed in the germinal layers of embryo and adult mouse brain: increased expression in N-CAM-deficient mice.

    Science.gov (United States)

    Muraille, E; Dassesse, D; Vanderwinden, J M; Cremer, H; Rogister, B; Erneux, C; Schiffmann, S N

    2001-01-01

    The germinative ventricular zone of embryonic brain contains neural lineage progenitor cells that give rise to neurons, astrocytes and oligodendrocytes. The ability to generate neurons persists at adulthood in restricted brain areas. During development, many growth factors exert their effects by interacting with tyrosine kinase receptors and activate the phosphatidylinositol 3-kinase and the Ras/MAP kinase pathways. By its ability to modulate these pathways, the recently identified Src homology 2 domain-containing inositol polyphosphate 5-phosphatase 2, SHIP2, has the potential to regulate neuronal development. Using in situ hybridization technique with multiple synthetic oligonucleotides, we demonstrated that SHIP2 mRNA was highly expressed in the ventricular zone at early embryonic stages and subventricular zones at latter stages of brain and spinal cord and in the sympathetic chain. No significant expression was seen in differentiated fields. This restricted expression was maintained from embryonic day 11.5 to birth. In the periphery, large expression was detected in muscle and kidney and moderate expression in thyroid, pituitary gland, digestive system and bone. In the adult brain, SHIP2 was mainly restricted in structures containing neural stem cells such as the anterior subventricular zone, the rostral migratory stream and the olfactory tubercle. SHIP2 was also detected in the choroid plexuses and the granular layer of the cerebellum. The specificity of SHIP2 expression in neural stem cells was further demonstrated by (i) the dramatic increase in SHIP2 mRNA signal in neural cell adhesion molecule (N-CAM)-deficient mice, which present an accumulation of progenitor cells in the anterior subventricular zone and the rostral migratory stream, (ii) the abundant expression of 160-kDa SHIP2 by western blotting in proliferating neurospheres in culture and its downregulation in non-proliferating differentiated neurospheres. In conclusion, the close correlation between

  17. Polymer coating, germination and vigor of broccoli seeds

    Directory of Open Access Journals (Sweden)

    Almeida Celina de

    2005-01-01

    Full Text Available Brassica oleracea var italica occupies a special place in the internal and external market of vegetables seeds. Vegetables producers demand seeds with high degree of purity, germination and vigor, since seeds' quality is the basis for the success of the production. In this work, broccoli seeds were coated in a spouted bed, by an aqueous suspension of hidroxy-ethyl-cellulose. Effects of the operating variables: spouting air temperature, atomizing air pressure and coating suspension flow rate over the dependent variables: seeds germination, seeds accelerated aging and the speed of seeds germination in soil, were investigated in a factorial scheme trial. The maximum processing time was 120 min. A totally randomized experiment evaluated and compared seeds germination and vigor of the coated and non-coated seeds. There was no identifiable, pronounced difference on germination of coated and non-coated seeds, accelerated aging of seeds, and speed of seeds germination in the soil. Coating with hidroxy-ethyl-cellulose in the spouted bed did not alter broccoli seeds physiologic quality. The surface of coated seeds presented satisfactory distribution and spreading of the polymer film, uniform and individual coating and homogeneous aspect.

  18. [Study on morphology, quality and germination characteristics of Acanthopanax trifoliatus seeds under different habitats].

    Science.gov (United States)

    Xiao, Juan

    2014-05-01

    To preliminary explore the difference of the morphological, quality and germinal characteristics of Acanthopanax trifoliatus seeds under different habitats. Collect the wild seeds from different habitats in West Mountain, and then observe their external appearances and internal structure, and test the thousand seeds weight,water content and seed vigor. What's more, the influence to germination rates of the seeds from different temperatures and light intensities in artificial bioclimatic chamber was studied. Orthogonal test in experimental plots was carried out to screen the different sowing dates, matrix types and soil depths which may influence germination rate. The external appearances and quality characteristics of wild seeds from three habitats were different. Seeds could germinate in the both light and dark, the germination rate of the habitat II was as high as 70.5% at the optimum temperature 20 degrees C in artificial bioclimatic chamber. The optimal combination A1, B1, C1 was screened out through orthogonal test, namely, the germination rate would be the highest when the seeds sowed in autumn covering with 2 cm depth of matrix type which component of the ratio of soil, sand and organic fertilizer was 6: 3: 1. There was significant difference in the morphology and germination rate of the three habitats seeds. The habitat II seeds were the optimal choice when culture seedling. The influences of different temperatures on germination rate were different, and the dried seeds should sow in current autumn, better than the next spring.

  19. Germination and storage of pollen

    NARCIS (Netherlands)

    Visser, T.

    1955-01-01

    Germination of pear pollen markedly improved when boric acid was added to the medium. The pollen was more sensitive to boron in water than in 10 % sugar solution. Supplying weak solutions of boron to pear branches before flowering resulted in a good germination of the pollen in sugar solution withou

  20. The generation of germinal centers

    NARCIS (Netherlands)

    Kroese, Fransciscus Gerardus Maria

    1987-01-01

    Germinal centers are clusters of B lymphoblastoid cells that develop after antigenic stimulation in follicles of peripheral lymphoid organs. These structures are thought to play a major role in the generation of B memory cells. This thesis is dealing with several aspects of these germinal centers. I

  1. Dormancy and germination: How does the crop seed decide?

    Science.gov (United States)

    Shu, K; Meng, Y J; Shuai, H W; Liu, W G; Du, J B; Liu, J; Yang, W Y

    2015-11-01

    Whether seeds germinate or maintain dormancy is decided upon through very intricate physiological processes. Correct timing of these processes is most important for the plants life cycle. If moist conditions are encountered, a low dormancy level causes pre-harvest sprouting in various crop species, such as wheat, corn and rice, this decreases crop yield and negatively impacts downstream industrial processing. In contrast, a deep level of seed dormancy prevents normal germination even under favourable conditions, resulting in a low emergence rate during agricultural production. Therefore, an optimal seed dormancy level is valuable for modern mechanised agricultural systems. Over the past several years, numerous studies have demonstrated that diverse endogenous and environmental factors regulate the balance between dormancy and germination, such as light, temperature, water status and bacteria in soil, and phytohormones such as ABA (abscisic acid) and GA (gibberellic acid). In this updated review, we highlight recent advances regarding the molecular mechanisms underlying regulation of seed dormancy and germination processes, including the external environmental and internal hormonal cues, and primarily focusing on the staple crop species. Furthermore, future challenges and research directions for developing a full understanding of crop seed dormancy and germination are also discussed.

  2. Portable Diagnostics and Rapid Germination

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Zachary Spencer [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-12-01

    In the Bioenergy and Defense Department of Sandia National Laboratories, characterization of the BaDx (Bacillus anthracis diagnostic cartridge) was performed and rapid germination chemistry was investigated. BaDx was tested with complex sample matrixes inoculated with Bacillus anthracis, and the trials proved that BaDx will detect Bacillus anthracis in a variety of the medium, such as dirt, serum, blood, milk, and horse fluids. The dimensions of the device were altered to accommodate an E. coli or Listeria lateral flow immunoassay, and using a laser printer, BaDx devices were manufactured to identify E. coli and Listeria. Initial testing with E. coli versions of BaDx indicate that the device will be viable as a portable diagnostic cartridge. The device would be more effective with faster bacteria germination; hence studies were performed the use of rapid germination chemistry. Trials with calcium dipicolinic acid displayed increased cell germination, as shown by control studies using a microplate reader. Upon lyophilization the rapid germination chemistry failed to change growth patterns, indicating that the calcium dipicolinic acid was not solubilized under the conditions tested. Although incompatible with the portable diagnostic device, the experiments proved that the rapid germination chemistry was effective in increasing cell germination.

  3. Effect of insulating layer material on RF-induced heating for external fixation system in 1.5 T MRI system.

    Science.gov (United States)

    Liu, Yan; Kainz, Wolfgang; Qian, Songsong; Wu, Wen; Chen, Ji

    2014-09-01

    The radio frequency (RF)-induced heating is a major concern when patients with medical devices are placed inside a magnetic resonance imaging (MRI) system. In this article, numerical studies are applied to investigate the potentials of using insulated materials to reduce the RF heating for external fixation devices. It is found that by changing the dielectric constant of the insulation material, the RF-induced heating at the tips of devices can be altered. This study indicates a potential technique of developing external fixation device with low MRI RF heating.

  4. seed germination and seedlings growth

    African Journals Online (AJOL)

    STORAGESEVER

    2007-12-17

    Dec 17, 2007 ... African Journal of Biotechnology Vol. 6 (24), pp. 2792-2802 ... needed for rapid cell respiration during germination, however, abscisic ... PAGE) was carried out in a vertical slab gel apparatus as described by Laemmli (1970).

  5. The site effect on germinability of mugwort (Artemisia vulgaris L. achenes

    Directory of Open Access Journals (Sweden)

    Jan Winkler

    2005-01-01

    Full Text Available Mugwort (Artemisia vulgaris L. extremely spreads on uncultivated agricultural land and expands to arable land. Three sites were chosen in the local area of Uherské Hradiště: field (arable land, balk (adjacent to arable land and rubble heap (distant from arable land. At each site, 50 plants were selected from which mature achenes were collected in 2002 and 2003. The achenes germinated in a laboratory at a room temperature and were subjected to various germination conditions. A part of them was exposed to the temperature of – 20 °C in a freezer, the other part was stored at a room temperature. The germination was carried out either on filter paper in Petri dishes or in 30 mm layer of siliceous sand. One part of the achenes germinated in daylight, the other part in Petri dishes in the dark. The achenes cultivated in siliceous sand were covered with a 5 mm layer of the sand. The results were statistically assessed using Unistat software, analysis of variance and methods of least significant differences (LSD. Total average germinability of mugwort achenes was 67,7 %. The differences in germinability of frozen (66,7 % and non-frozen (72,6 % achenes were not statistically significant. Germinability of the achenes that matured in 2003 (69,9 % was highly significantly higher than that of the achenes matured in 2002 (65,4 %. The achenes germinated highly significantly more (77,9 % in daylight as compared with those germinated in the dark (57,4 %. Germinability of the achenes that germinated in siliceous sand was highly significantly higher (70,7 % than of those that germinated in Petri dishes (64,7 %. Germinability of the achenes matured in the field (64,1 % was significantly lower in comparison with the germinability of the achenes from a balk (69,7 % and rubble heap (69,2 %. The results of germinability of the achenes that matured in a rubble heap and balk did not significantly differ.

  6. Precocious germination and its regulation in embryos of triticale caryopses

    Directory of Open Access Journals (Sweden)

    Stanisław Weidner

    2014-01-01

    Full Text Available Triticale var. Lasko embryos, isolated from grain gathered at milk ripeness, the beginning of wax ripeness and at full ripeness, were allowed to germinate for 48 h on agar with glucose. The highest incorporation of tritiated adenosine into polyribosomal RNA during germination was found in the ribosome fractions from embryos of grain gathered at full ripeness, lower incorporation was in preparations from embryos of milk ripe grain and the lowest in preparations from embryos of wax ripe grain. Different tendencies were observed in respect to the synthesis of ribosomal proteins. The highest incorporation of 14C-amino acids into ribosomal proteins was found in preparations of ribosome fractions from embryos of milk ripe grain, lower in preparations of embryos from fully ripe grain, the lowest in preparations of embryos from wax ripe grain. ABA (10-4 M completely inhibited the external symptoms of germination of immature embryos, while its inhibition of the synthesis of polyribosomal RNA and ribosomal proteins was greater the more mature the embryos that were germinated. The greatest stimulation of precocious germination by exogenous BA and GA3 was demonstrated in the least mature embryos isolated from milk ripe grain. Under the influence of both stimulators, an increase of the proportion of polyribosomes in the total ribosome fraction occurred in this sample, as did a rise in the intensity of ribosomal protein synthesis. The incorporation of 3H-adenosine into polyribosomal RNA, however, was lower than in the control sample. The results obtained suggest that the regulation of precocious germination of triticale embryos by phyto-hormones is not directly related to transcription.

  7. Identification of a hydrogen peroxide signalling pathway in the control of light-dependent germination in Arabidopsis.

    Science.gov (United States)

    Lariguet, Patricia; Ranocha, Philippe; De Meyer, Mireille; Barbier, Odile; Penel, Claude; Dunand, Christophe

    2013-08-01

    Germination is controlled by external factors, such as temperature, water, light and by hormone balance. Recently, reactive oxygen species (ROS) have been shown to act as messengers during plant development, stress responses and programmed cell death. We analyzed the role of ROS during germination and demonstrated that ROS in addition to their role as cell wall loosening factor are essential signalling molecules in this process. Indeed, we showed that ROS are released prior to endosperm rupture, that their production is required for germination, and that class III peroxidases, as ROS level regulators, colocalized with ROS production. Among ROS, H2O2 modifies, during germination early steps, the expression of genes encoding for enzymes regulating ROS levels. This pointing out a regulatory feedback loop for ROS production. Measurements of endogenous levels of ROS following application of GA and ABA suggested that ABA inhibits germination by repressing ROS accumulation, and that, conversely, GA triggers germination by promoting an increase of ROS levels. We followed the early visible steps of germination (testa and endosperm rupture) in Arabidopsis seeds treated by specific ROS scavengers and as the light quality perception is necessary for a regular germination, we examined the germination in presence of exogenous H2O2 in different light qualities. H2O2 either promoted germination or repressed germination depending on the light wavelengths, showing that H2O2 acts as a signal molecule regulating germination in a light-dependent manner. Using photoreceptors null-mutants and GA-deficient mutants, we showed that H2O2-dependent promotion of germination relies on phytochrome signalling, but not on cryptochrome signalling, and that ROS signalling requires GA signalling.

  8. A Clostridium difficile-Specific, Gel-Forming Protein Required for Optimal Spore Germination

    Directory of Open Access Journals (Sweden)

    M. Lauren Donnelly

    2017-01-01

    Full Text Available Clostridium difficile is a Gram-positive spore-forming obligate anaerobe that is a leading cause of antibiotic-associated diarrhea worldwide. In order for C. difficile to initiate infection, its aerotolerant spore form must germinate in the gut of mammalian hosts. While almost all spore-forming organisms use transmembrane germinant receptors to trigger germination, C. difficile uses the pseudoprotease CspC to sense bile salt germinants. CspC activates the related subtilisin-like protease CspB, which then proteolytically activates the cortex hydrolase SleC. Activated SleC degrades the protective spore cortex layer, a step that is essential for germination to proceed. Since CspC incorporation into spores also depends on CspA, a related pseudoprotease domain, Csp family proteins play a critical role in germination. However, how Csps are incorporated into spores remains unknown. In this study, we demonstrate that incorporation of the CspC, CspB, and CspA germination regulators into spores depends on CD0311 (renamed GerG, a previously uncharacterized hypothetical protein. The reduced levels of Csps in gerG spores correlate with reduced responsiveness to bile salt germinants and increased germination heterogeneity in single-spore germination assays. Interestingly, asparagine-rich repeat sequences in GerG’s central region facilitate spontaneous gel formation in vitro even though they are dispensable for GerG-mediated control of germination. Since GerG is found exclusively in C. difficile, our results suggest that exploiting GerG function could represent a promising avenue for developing C. difficile-specific anti-infective therapies.

  9. A Clostridium difficile-Specific, Gel-Forming Protein Required for Optimal Spore Germination

    Science.gov (United States)

    Donnelly, M. Lauren; Li, William; Li, Yong-qing; Hinkel, Lauren; Setlow, Peter

    2017-01-01

    ABSTRACT Clostridium difficile is a Gram-positive spore-forming obligate anaerobe that is a leading cause of antibiotic-associated diarrhea worldwide. In order for C. difficile to initiate infection, its aerotolerant spore form must germinate in the gut of mammalian hosts. While almost all spore-forming organisms use transmembrane germinant receptors to trigger germination, C. difficile uses the pseudoprotease CspC to sense bile salt germinants. CspC activates the related subtilisin-like protease CspB, which then proteolytically activates the cortex hydrolase SleC. Activated SleC degrades the protective spore cortex layer, a step that is essential for germination to proceed. Since CspC incorporation into spores also depends on CspA, a related pseudoprotease domain, Csp family proteins play a critical role in germination. However, how Csps are incorporated into spores remains unknown. In this study, we demonstrate that incorporation of the CspC, CspB, and CspA germination regulators into spores depends on CD0311 (renamed GerG), a previously uncharacterized hypothetical protein. The reduced levels of Csps in gerG spores correlate with reduced responsiveness to bile salt germinants and increased germination heterogeneity in single-spore germination assays. Interestingly, asparagine-rich repeat sequences in GerG’s central region facilitate spontaneous gel formation in vitro even though they are dispensable for GerG-mediated control of germination. Since GerG is found exclusively in C. difficile, our results suggest that exploiting GerG function could represent a promising avenue for developing C. difficile-specific anti-infective therapies. PMID:28096487

  10. DELAY OF GERMINATION 1 mediates a conserved coat-dormancy mechanism for the temperature- and gibberellin-dependent control of seed germination

    Science.gov (United States)

    Graeber, Kai; Linkies, Ada; Steinbrecher, Tina; Mummenhoff, Klaus; Tarkowská, Danuše; Turečková, Veronika; Ignatz, Michael; Sperber, Katja; Voegele, Antje; de Jong, Hans; Urbanová, Terezie; Strnad, Miroslav; Leubner-Metzger, Gerhard

    2014-01-01

    Seed germination is an important life-cycle transition because it determines subsequent plant survival and reproductive success. To detect optimal spatiotemporal conditions for germination, seeds act as sophisticated environmental sensors integrating information such as ambient temperature. Here we show that the DELAY OF GERMINATION 1 (DOG1) gene, known for providing dormancy adaptation to distinct environments, determines the optimal temperature for seed germination. By reciprocal gene-swapping experiments between Brassicaceae species we show that the DOG1-mediated dormancy mechanism is conserved. Biomechanical analyses show that this mechanism regulates the material properties of the endosperm, a seed tissue layer acting as germination barrier to control coat dormancy. We found that DOG1 inhibits the expression of gibberellin (GA)-regulated genes encoding cell-wall remodeling proteins in a temperature-dependent manner. Furthermore we demonstrate that DOG1 causes temperature-dependent alterations in the seed GA metabolism. These alterations in hormone metabolism are brought about by the temperature-dependent differential expression of genes encoding key enzymes of the GA biosynthetic pathway. These effects of DOG1 lead to a temperature-dependent control of endosperm weakening and determine the optimal temperature for germination. The conserved DOG1-mediated coat-dormancy mechanism provides a highly adaptable temperature-sensing mechanism to control the timing of germination. PMID:25114251

  11. Effect of chemical and physical factors to improve the germination rate of Echinacea angustifolia seeds.

    Science.gov (United States)

    Chuanren, Duan; Bochu, Wang; Wanqian, Liu; Jing, Chen; Jie, Lian; Huan, Zhao

    2004-09-01

    Seeds of Echinacea angustifolia are known for their deep dormancy. In this paper, we studied the responses of E. angustifolia seeds to some chemical and physical factors, such as scarification, chilling (5 degrees C) period, light and applied BA (6-benzylaminopurine), GA3 (gibberellic acid) and sound stimulation. When the seed coat layers were removed, the germination rate grew up from 6 to 20% (incubated in light) and the mean time germination (MTG) was reduced from 18 to 6.6 days. On the basis of layers-removed, chilling and continuous light gave significantly higher germination rate (up to 70%). Compare the data of seeds chilled by 0, 6, 12, 18 and 24 days, the maximum germination rate (up to 70%) achieved at 18-days chilling treatment. Further increases in the chilling period could slightly improve germination. Exogenous application of 0.1, 0.2, 0.3 mg/L GA3 or BA in the previous pretreatment increased germination to 78, 90 and 84% or 76, 86 and 84%, respectively. Obviously, the best concentration of GA or BA is 0.3 mg/L. And the GA3 or BA treatment shortened the MTG to about 4 days. The influence of sound stimulation was also tested in the experiment. The result showed that one 100 dB and 1000 Hz sound wave (sine-wave) was beneficial to the germination of E. angustifolia seeds.

  12. Role of YpeB in Cortex Hydrolysis during Germination of Bacillus anthracis Spores

    OpenAIRE

    2014-01-01

    The infectious agent of the disease anthrax is the spore of Bacillus anthracis. Bacterial spores are extremely resistant to environmental stresses, which greatly hinders spore decontamination efforts. The spore cortex, a thick layer of modified peptidoglycan, contributes to spore dormancy and resistance by maintaining the low water content of the spore core. The cortex is degraded by germination-specific lytic enzymes (GSLEs) during spore germination, rendering the cells vulnerable to common ...

  13. Ethylene, seed germination, and epinasty.

    Science.gov (United States)

    Stewart, E R; Freebairn, H T

    1969-07-01

    Ethylene activity in lettuce seed (Lactuca satina) germination and tomato (Lycopersicon esculentum) petiole epinasty has been characterized by using heat to inhibit ethylene synthesis. This procedure enabled a separation of the production of ethylene from the effect of ethylene. Ethylene was required in tomato petioles to produce the epinastic response and auxin was found to be active in producing epinasty through a stimulation of ethylene synthesis with the resulting ethylene being responsible for the epinasty. In the same manner, it was shown that gibberellic acid stimulated ethylene synthesis in lettuce seeds. The ethylene produced then in turn stimulated the seeds to germinate. It was hypothesized that ethylene was the intermediate which caused epinasty or seed germination. Auxin and gibberellin primarily induced their response by stimulating ethylene production.

  14. Characterization of bacterial spore germination using integrated phase contrast microscopy, Raman spectroscopy, and optical tweezers.

    Science.gov (United States)

    Kong, Lingbo; Zhang, Pengfei; Setlow, Peter; Li, Yong-Qing

    2010-05-01

    We present a methodology that combines external phase contrast microscopy, Raman spectroscopy, and optical tweezers to monitor a variety of changes during the germination of single Bacillus cereus spores in both nutrient (l-alanine) and non-nutrient (Ca-dipicolinic acid (DPA)) germinants with a temporal resolution of approximately 2 s. Phase contrast microscopy assesses changes in refractility of individual spores during germination, while Raman spectroscopy gives information on changes in spore-specific molecules. The results obtained include (1) the brightness of the phase contrast image of an individual dormant spore is proportional to the level of CaDPA in that spore; (2) the end of the first Stage of germination, revealed as the end of the rapid drop in spore refractility by phase contrast microscopy, precisely corresponds to the completion of the release of CaDPA as revealed by Raman spectroscopy; and (3) the correspondence between the rapid drop in spore refractility and complete CaDPA release was observed not only for spores germinating in the well-controlled environment of an optical trap but also for spores germinating when adhered on a microscope coverslip. Using this latter method, we also simultaneously characterized the distribution of the time-to-complete-CaDPA release (T(release)) of hundreds of individual B. cereus spores germinating with both saturating and subsaturating concentrations of l-alanine and with CaDPA.

  15. Activation of rape (Brassica napus L. embryo during seed germination. V. The first zones of ultrastructural changes and their expansion

    Directory of Open Access Journals (Sweden)

    Mieczysław Karaś

    2014-01-01

    Full Text Available In the germinating rape embryo the columella and basal part of hypocotyl undergo earliest activation. Its first ultrastructural symptom is the appearance of numerous ER vesicles after 3-6 h of seed swelling. Their number is the highest in the external layers of the columella and decreases in basipetal direction. Dermatogen cells in the basal zone of the hypocotyl contain the greatest amount of ER structures, whereas decreasing amounts are found in both directions along the embryo axis and centripetally. Further changes in the ER spread in a similar order. The vesicles merge and form a tubular and plate-like ER. Then, they disappear and are replaced by tubular and vesicular forms. The changes in the ER are gradually followed by ultrastructural symptoms of activation of mitochondria, plastids and dictyosomes. The highest number of ER structures and other organelles accumulate in root cells shortly before piercing of the seed coat. After germination their amount decreases and remains almost stable.

  16. Effect of cigarette smoke on seed germination.

    Science.gov (United States)

    Noble, R E

    2001-02-21

    The effect of cigarette smoke was studied on the germination of radish, kale, lettuce, amaranth, wheat, rice, barley and rye seeds. It was found that such smoke markedly retarded, in all cases, the rate of germination. Furthermore, cigarette smoke caused a retardation of the levels of certain enzymes (alpha-amylase or lysozyme) known to be significant in the germination of these seeds.

  17. Clinic Effect of Layers Adjusting External Application Therapy on Knee Osteoarthritis%“易层”贴敷疗法治疗膝骨性关节炎的临床疗效观察

    Institute of Scientific and Technical Information of China (English)

    王培民; 黄国淳; 丁亮; 马勇

    2014-01-01

    This study was aimed to evaluate clinic effect of the layers adjusting external application therapy on knee osteoarthritis (OA). A total of 240 knee OA cases were randomly divided into the treatment group and the control group, with 120 cases in each group. The layers adjusting external application therapy was used in the treatment group. And analgesic plaster of compound of rhizoma arisaematis was used in the control group. The treatment was continued for 21 days. Then, 14-day follow-up was given after the treatment course. There were a total of 35 days. Observations were made on indexes of pain, swelling and joint dysfunction with quantitative scoring. The results showed that the total effective rate was 98.2%in the treatment group, and 83.9%in the control group. The indexes of pain, swelling and joint dysfunction were markedly improved in the treatment group as compared with the control group (P<0.01). It was concluded that the layers adjusting external application therapy was effective on the treat-ment of knee OA.%目的:观察评价“易层”贴敷疗法治疗膝骨性关节炎的临床疗效研究。方法:将240例患者随机分为治疗组和对照组,每组各120例。治疗组使用“易层”贴敷疗法治疗,对照组使用复方南星止痛膏治疗,治疗21天,治疗结束后再随访14天,共35天。观察两组疼痛、肿胀、关节功能障碍的改善情况,进行量化评分。结果:治疗组总有效率98.2%,对照组83.9%;治疗组在疼痛、肿胀及关节功能障碍的指标积分改善显著优于对照组(P<0.01)。结论:研究结果表明,“易层”贴敷疗法治疗膝骨性关节炎有良好的疗效。

  18. Effect of Rashba spin-orbit coupling and external magnetic field on electronic minibands in highly strained one-layer quantum ring superlattice

    Science.gov (United States)

    Mughnetsyan, Vram; Manaselyan, Aram; Kirakosyan, Albert

    2017-04-01

    The Rashba spin-orbit coupling for electronic states in a strained one layer superlattice, composed of InAs/GaAs quantum rings has been investigated in the presence of uniform magnetic field directed perpendicular to the lattice plane. The dispersion surfaces and the energy dependencies on the magnetic field induction are obtained by the exact diagonalization procedure using the Fourier transformation to the momentum space. The characteristic splitting of the mini-bands as well as the crossings of the dispersion surfaces at the high symmetry points in the Brillouin zone have been observed. An upward shift of the minibands by about 60 meV due to strain in superlattice has been observed.

  19. Initiation of bacterial spore germination.

    Science.gov (United States)

    Vary, J C; Halvorson, H O

    1968-04-01

    To investigate the problem of initiation in bacterial spore germination, we isolated, from extracts of dormant spores of Bacillus cereus strain T and B. licheniformis, a protein that initiated spore germination when added to a suspension of heat-activated spores. The optimal conditions for initiatory activity of this protein (the initiator) were 30 C in 0.01 to 0.04 m NaCl and 0.01 m tris(hydroxymethyl)aminomethane (pH 8.5). The initiator was inhibited by phosphate but required two co-factors, l-alanine (1/7 of K(m) for l-alanine-inhibited germination) and nicotinamide adenine dinucleotide (1.25 x 10(-4)m). In the crude extract, the initiator activity was increased 3.5-fold by heating the extract at 65 C for 10 min, but the partially purified initiator preparation was completely heat-sensitive (65 C for 5 min). Heat stability could be conferred on the purified initiator by adding 10(-3)m dipicolinic acid. A fractionation of this protein that excluded l-alanine dehydrogenase and adenosine deaminase from the initiator activity was developed. The molecular weight of the initiator was estimated as 7 x 10(4). The kinetics of germination in the presence of initiator were examined at various concentrations of l-alanine and nicotinamide adenine dinucleotide.

  20. Habitat specialization through germination cueing

    DEFF Research Database (Denmark)

    Ten Brink, Dirk-Jan; Hendriksma, Harmen; Bruun, Hans Henrik

    2013-01-01

    This study examined the adaptive association between seed germination ecology and specialization to either forest or open habitats across a range of evolutionary lineages of seed plants, in order to test the hypotheses that (1) species' specialization to open vs. shaded habitats is consistently...

  1. Germination Requirements of Bacillus macerans Spores

    Science.gov (United States)

    Sacks, L. E.; Thompson, P. A.

    1971-01-01

    2-Phenylacetamide is an effective germinant for spores of five strains of Bacillus macerans, particularly in the presence of fructose. Benzyl penicillin, the phenyl acetamide derivative of penicillin, and phenylacetic acid are also good germinants. l-Asparagine is an excellent germinant for four strains. α-Amino-butyric acid is moderately effective. Pyridoxine, pyridoxal, adenine, and 2,6-diaminopurine are potent germinants for NCA strain 7X1 only. d-Glucose is a powerful germinant for strain B-70 only. d-Fructose and d-ribose strongly potentiate germination induced by other germinants (except l-asparagine) but have only weak activity by themselves. Niacinamide and nicotinamide-adenine dinucleotide, inactive by themselves, are active in the presence of fructose or ribose. Effects of pH, ion concentration, and temperature are described. PMID:4251279

  2. Beyond gibberellins and abscisic acid: how ethylene and jasmonates control seed germination.

    Science.gov (United States)

    Linkies, Ada; Leubner-Metzger, Gerhard

    2012-02-01

    Appropriate responses of seeds and fruits to environmental factors are key traits that control the establishment of a species in a particular ecosystem. Adaptation of germination to abiotic stresses and changing environmental conditions is decisive for fitness and survival of a species. Two opposing forces provide the basic physiological mechanism for the control of seed germination: the increasing growth potential of the embryo and the restraint weakening of the various covering layers (seed envelopes), including the endosperm which is present to a various extent in the mature seeds of most angiosperms. Gibberellins (GA), abscisic acid (ABA) and ethylene signaling and metabolism mediate environmental cues and in turn influence developmental processes like seed germination. Cross-species work has demonstrated that GA, ABA and ethylene interact during the regulation of endosperm weakening, which is at least partly based on evolutionarily conserved mechanisms. We summarize the recent progress made in unraveling how ethylene promotes germination and acts as an antagonist of ABA. Far less is known about jasmonates in seeds for which we summarize the current knowledge about their role in seeds. While it seems very clear that jasmonates inhibit germination, the results obtained so far are partly contradictory and depend on future research to reach final conclusions on the mode of jasmonate action during seed germination. Understanding the mechanisms underlying the control of seed germination and its hormonal regulation is not only of academic interest, but is also the ultimate basis for further improving crop establishment and yield, and is therefore of common importance.

  3. Dormant ascospores of Talaromyces macrosporus are activated to germinate after treatment with ultra high pressure

    NARCIS (Netherlands)

    Dijksterhuis, J; Teunissen, P G M

    2004-01-01

    AIMS: Ascospores of Talaromyces macrosporus are constitutively dormant and germinate after a strong external shock, classically a heat treatment. This fungus is used as a model system to study heat resistance leading to food spoilage after pasteurization. This study evaluates the effect of high pres

  4. Dormant ascospores of Talaromyces macrosporus are activated to germinate after treatment with ultra high pressure

    NARCIS (Netherlands)

    Dijksterhuis, G.B.; Teunissen, P.G.M.

    2004-01-01

    Aims: Ascospores of Talaromyces macrosporus are constitutively dormant and germinate after a strong external shock, classically a heat treatment. This fungus is used as a model system to study heat resistance leading to food spoilage after pasteurization. This study evaluates the effect of high pres

  5. Effects of priming on seed germination and germination

    Directory of Open Access Journals (Sweden)

    azade hoseiny

    2009-06-01

    Full Text Available Four osmotica (water, hydrochloric acid (HCl 0.5 N, (HCl 0.1 N, sodium chloride 1.5 N and polyethylene glycol-6000 (PEG 6000 were used for priming of four varieties of sugar beet (Beta vulgaris namely KWS, Universe, Afshari and Orbise. The type of experiment was Factorial on the basis of completely randomized design with three replications. Fifthy seeds were washed by distilled water, HCl, PEG 6000 and NaCl and then each of the above treatments were applied for two hours. The most promising treatments in terms of the rate and percentage of germination were water and HCl. Radicle and coleoptil lengths were shorter in NaCl and PEG is comparison with HCl and water. Varieties of KWS, Universe and Orbice had longer shoots that shows the restage of them was more than other varieties and the treatment of HCl increased the percentage and rate of germination.

  6. Supervised Learning of Two-Layer Perceptron under the Existence of External Noise — Learning Curve of Boolean Functions of Two Variables in Tree-Like Architecture —

    Science.gov (United States)

    Uezu, Tatsuya; Kiyokawa, Shuji

    2016-06-01

    We investigate the supervised batch learning of Boolean functions expressed by a two-layer perceptron with a tree-like structure. We adopt continuous weights (spherical model) and the Gibbs algorithm. We study the Parity and And machines and two types of noise, input and output noise, together with the noiseless case. We assume that only the teacher suffers from noise. By using the replica method, we derive the saddle point equations for order parameters under the replica symmetric (RS) ansatz. We study the critical value αC of the loading rate α above which the learning phase exists for cases with and without noise. We find that αC is nonzero for the Parity machine, while it is zero for the And machine. We derive the exponents barβ of order parameters expressed as (α - α C)bar{β} when α is near to αC. Furthermore, in the Parity machine, when noise exists, we find a spin glass solution, in which the overlap between the teacher and student vectors is zero but that between student vectors is nonzero. We perform Markov chain Monte Carlo simulations by simulated annealing and also by exchange Monte Carlo simulations in both machines. In the Parity machine, we study the de Almeida-Thouless stability, and by comparing theoretical and numerical results, we find that there exist parameter regions where the RS solution is unstable, and that the spin glass solution is metastable or unstable. We also study asymptotic learning behavior for large α and derive the exponents hat{β } of order parameters expressed as α - hat{β } when α is large in both machines. By simulated annealing simulations, we confirm these results and conclude that learning takes place for the input noise case with any noise amplitude and for the output noise case when the probability that the teacher's output is reversed is less than one-half.

  7. Dynamic compensation temperature in the kinetic spin-1 Ising model in an oscillating external magnetic field on alternate layers of a hexagonal lattice

    Science.gov (United States)

    Temizer, Ümüt; Keskin, Mustafa; Canko, Osman

    2009-10-01

    The dynamic behavior of a two-sublattice spin-1 Ising model with a crystal-field interaction ( D) in the presence of a time-varying magnetic field on a hexagonal lattice is studied by using the Glauber-type stochastic dynamics. The lattice is formed by alternate layers of spins σ=1 and S=1. For this spin arrangement, any spin at one lattice site has two nearest-neighbor spins on the same sublattice, and four on the other sublattice. The intersublattice interaction is antiferromagnetic. We employ the Glauber transition rates to construct the mean-field dynamical equations. Firstly, we study time variations of the average magnetizations in order to find the phases in the system, and the temperature dependence of the average magnetizations in a period, which is also called the dynamic magnetizations, to obtain the dynamic phase transition (DPT) points as well as to characterize the nature (continuous and discontinuous) of transitions. Then, the behavior of the total dynamic magnetization as a function of the temperature is investigated to find the types of the compensation behavior. Dynamic phase diagrams are calculated for both DPT points and dynamic compensation effect. Phase diagrams contain the paramagnetic (p) and antiferromagnetic (af) phases, the p+af and nm+p mixed phases, nm is the non-magnetic phase, and the compensation temperature or the L-type behavior that strongly depend on the interaction parameters. For D3.8275, H0 is the magnetic field amplitude, the compensation effect does not appear in the system.

  8. Ultrastructure and germination of Vitis vinifera cv. Loureiro pollen.

    Science.gov (United States)

    Abreu, I; Costa, I; Oliveira, M; Cunha, M; de Castro, R

    2006-08-01

    The cultivar Loureiro of Vitis vinifera is one of the most economically important, recommended in almost the totality of the Região Demarcada dos Vinhos Verdes. In vineyards, the grape productivity of this cultivar is normal while in others it is extremely low. The aim of this work was to study the morphology and germination of Vitis vinifera cv. Loureiro pollen with high and low productivity. The pollen grain was examined under light, transmission and scanning electron microscopy. Typically V. vinifera pollen present three furrows but in the cultivar Loureiro we found tricolporated and acolporated (without furrows or pores) pollen grains. Both pollen types present generative and vegetative cells with the usual aspect and a dense cytoplasm rich in organelles. In the acolporated pollen a continuous exine layer and an irregular intine layer were observed. Differences were found in the starch accumulation, since only in tricolporated pollen abundant plastids filled with numerous starch granules were observed. To determine the causes of the low productivity of this cultivar we tested pollen viability by the fluorochromatic reaction and pollen germinability by in vitro assays. We observed that the acolporated pollen grain is viable, but no germination was recorded.

  9. Factors influencing seed germination in Cerrado grasses

    Directory of Open Access Journals (Sweden)

    Rosana Marta Kolb

    2016-03-01

    Full Text Available Few studies address the ecology of herbs of Cerrado grasslands, which are ecosystems where the long dry season, high temperatures, insolation, fire and invasive grasses greatly influencing germination and the establishment of plants. We assessed germination of 13 species of Poaceae from Cerrado grasslands under nursery conditions or in germination chambers, the latter with i recently collected seeds and seeds after six months storage, ii under constant and alternating temperatures, and iii in the presence and absence of light. Germinability, mean germination time (MGT and required light were quantified to elucidate factors involved in successful germination. Germinability was low for most grasses, probably because of low seed viability. For most species, germinability and MGT were not altered by seed storage. Germination percentages were higher at alternating temperatures and in the presence of light, factors that are more similar to natural environmental situations compared with constant temperature or the absence of light. Our findings indicate that alternating temperatures and light incidence are key factors for germination of species of Poaceae. The maintenance of these environmental factors, which are crucial for the conservation of Cerrado grasslands, depends on appropriate management interventions, such as fire management and the control of biological invasion.

  10. Effect of industrial pollution on seed germination

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, M.Z.; Qadir, S.A.

    1973-01-01

    The germination behavior of seeds in polluted waters and polluted soil extracts was found to be identical, only a few species behaved differently. Prosopis juliflora, Haloxylon recurvum, Acacia senegal showed best germination in the two conditions but Prosopis juliflora was the most resistant to pollution. In Suaeda fruticosa no germination took place in the control treatment whereas highest germination (70%) was seen in treatment with polluted soil extract of EPLA. Blepharis sindica showed a stimulating effect of polluted water on germination, whereas low germination was observed when their seeds were treated with the soil extract of the same site. 40% germination of Suaeda monoica was seen in polluted water of Carbon and Ribbon Mfg. Co., whereas 30% germination was found in a control treatment. Low percentage of germination was found when the seeds of Cassia holosericea were treated with polluted waters of different industries as compared to soil extract treatments of the same industries. Datura alba showed 50, 30 and 10% seed germination in polluted soil extract of Carbon and Ribbon Mfg. Co., in control and in polluted water of Darbar Soap Works, respectively. 5 references, 1 table.

  11. Regulation of Clostridium difficile spore germination by the CspA pseudoprotease domain.

    Science.gov (United States)

    Kevorkian, Yuzo; Shirley, David J; Shen, Aimee

    2016-03-01

    Clostridium difficile is a spore-forming obligate anaerobe that is a leading cause of healthcare-associated infections. C. difficile infections begin when its metabolically dormant spores germinate in the gut of susceptible individuals. Binding of bile salt germinants to the Csp family pseudoprotease CspC triggers a proteolytic signaling cascade consisting of the Csp family protease CspB and the cortex hydrolase SleC. Conserved across many of the Clostridia, Csp proteases are subtilisin-like serine proteases that activate pro-SleC by cleaving off its inhibitory pro-peptide. Active SleC degrades the protective cortex layer, allowing spores to resume metabolism and growth. This signaling pathway, however, is differentially regulated in C. difficile, since CspC functions both as a germinant receptor and regulator of CspB activity. CspB is also produced as a fusion to a catalytically inactive CspA domain that subsequently undergoes interdomain processing during spore formation. In this study, we investigated the role of the CspA pseudoprotease domain in regulating C. difficile spore germination. Mutational analyses revealed that the CspA domain controls CspC germinant receptor levels in mature spores and is required for optimal spore germination, particularly when CspA is fused to the CspB protease. During spore formation, the YabG protease separates these domains, although YabG itself is dispensable for germination. Bioinformatic analyses of Csp family members suggest that the CspC-regulated signaling pathway characterized in C. difficile is conserved in related Peptostreptococcaceae family members but not in the Clostridiaceae or Lachnospiraceae. Our results indicate that pseudoproteases play critical roles in regulating C. difficile spore germination and highlight that diverse mechanisms control spore germination in the Clostridia.

  12. Proteomics of Rice Seed Germination

    Institute of Scientific and Technical Information of China (English)

    Dongli He; Chao Han; Xiaojian Yin; Hui Zhang; Pingfang Yang

    2012-01-01

    Seed germination is a complex physiological which starts from the uptake of water by the dry seeds and ends at the protrusion of the radicle.In order to elucidate the mechanism of rice seed germination,we have conducted a systematic proteomic analyses combining with 1-D via LC MS/MS,comparative 2-DE and iTRAQ techniques using the whole seed or dissected embryos and endosperm.During rice seed germination,the embryo and endosperm played different roles.The seed weight increased and complied by a triphasic model.Phase I accompanied with rapid seed water-up-take,the embryo produced gibberellic acid (GA) and diffused to aleurone and then prepared to initiate a signaling cascade to drive the reserves degradation in the starchy endosperm.Phase II is the most important stage for metabolic reactions reactivation,the reserves mobilization,cell construction respiration,cell wall loosening and coleoptile elongation,most of the metabolism related proteins sorted to different pathways were identified at 24 h after imbibition,but the metabolism of nucleotides was not active at this stage for few related proteins have been involved.The degradation of seed maturation and desiccation-associated proteins seemed to be earlier than that of the storage proteins and starch.The glycolysis was the main pathway for energy and substance providing.Phase III is another rapid water-uptake stage accompanying with TCA and aerobic respiration strengthening,cell division initiation and the radical protrusion.Interesting,both biosynthesis and degradation of the same macromolecule were concurrence even in the dry seed,which implied the sequentially matabolic and regulatory events triggered by water uptake during rice seed germination have been programmed during seed maturation.

  13. Differential expression of wheat aspartic proteinases, WAP1 and WAP2, in germinating and maturing seeds.

    Science.gov (United States)

    Tamura, Tomoko; Terauchi, Kaede; Kiyosaki, Toshihiro; Asakura, Tomiko; Funaki, Junko; Matsumoto, Ichiro; Misaka, Takumi; Abe, Keiko

    2007-04-01

    Two aspartic proteinase (AP) cDNA clones, WAP1 and WAP2, were obtained from wheat seeds. Proteins encoded by these clones shared 61% amino acid sequence identity. RNA blotting analysis showed that WAP1 and WAP2 were expressed in both germinating and maturing seeds. The level of WAP2 mRNA expression was clearly weaker than that of WAP1 in all tissues of seeds during germination and maturation. APs purified from germinating seeds were enzymatically active and digested the wheat storage protein, gluten. To elucidate the physiological functions of WAP1 and WAP2 in seeds, we investigated the localisation of WAP1 and WAP2 by in situ hybridisation. In germinating seeds investigated 24h after imbibition, both WAP1 and WAP2 were expressed in embryos, especially in radicles and shoots, scutellum, and the aleurone layer. In maturing seeds, WAP1 was expressed in the whole embryo, with slightly stronger expression in radicles and shoots. WAP1 was also expressed in the aleurone layer 3 weeks after flowering. Strong signals of WAP1 mRNA were detected in the whole embryo and aleurone layer 6 weeks after flowering. On the other hand, WAP2 was scarcely detected in seeds 3 weeks after flowering, and thereafter weak signals began to appear in the whole embryo. WAP1 and WAP2 were expressed widely in germinating and maturing seeds. Such diversity in site- and stage-specific expression of the two enzymes suggests their differential functions in wheat seeds.

  14. Recent advances in germination of Clostridium spores.

    Science.gov (United States)

    Olguín-Araneda, Valeria; Banawas, Saeed; Sarker, Mahfuzur R; Paredes-Sabja, Daniel

    2015-05-01

    Members of Clostridium genus are a diverse group of anaerobic spore-formers that includes several pathogenic species. Their anaerobic requirement enhances the importance of the dormant spore morphotype during infection, persistence and transmission. Bacterial spores are metabolically inactive and may survive for long times in the environment and germinate in presence of nutrients termed germinants. Recent progress with spores of several Clostridium species has identified the germinant receptors (GRs) involved in nutrient germinant recognition and initiation of spore germination. Signal transduction from GRs to the downstream effectors remains poorly understood but involves the release of dipicolinic acid. Two mechanistically different cortex hydrolytic machineries are present in Clostridium spores. Recent studies have also shed light into novel biological events that occur during spore formation (accumulation of transcriptional units) and transcription during early spore outgrowth. In summary, this review will cover all of the recent advances in Clostridium spore germination. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  15. Detecting Cortex Fragments During Bacterial Spore Germination.

    Science.gov (United States)

    Francis, Michael B; Sorg, Joseph A

    2016-06-25

    The process of endospore germination in Clostridium difficile, and other Clostridia, increasingly is being found to differ from the model spore-forming bacterium, Bacillus subtilis. Germination is triggered by small molecule germinants and occurs without the need for macromolecular synthesis. Though differences exist between the mechanisms of spore germination in species of Bacillus and Clostridium, a common requirement is the hydrolysis of the peptidoglycan-like cortex which allows the spore core to swell and rehydrate. After rehydration, metabolism can begin and this, eventually, leads to outgrowth of a vegetative cell. The detection of hydrolyzed cortex fragments during spore germination can be difficult and the modifications to the previously described assays can be confusing or difficult to reproduce. Thus, based on our recent report using this assay, we detail a step-by-step protocol for the colorimetric detection of cortex fragments during bacterial spore germination.

  16. Environmental Factors that Interfere in the Germination

    Directory of Open Access Journals (Sweden)

    Lisiane de Souza

    2014-12-01

    Full Text Available This paper refers to the application of experiments with sixth graders of elementary school, aiming motivation, skills development focused on observation, interpersonal relationships in teams, related to the various forms of language skills, as well to identify and resume misconceptions about the external (environmental factors required for seed germination, in order that the contents developed this year refer to the study of the earth, soil, water and air, among others, and that many students do not understand all the concepts and the importance of these factors for the existence of living beings. The experiments were organized in two stages, first to observe the influence of soil and another moment to observe the interference of water, air and light. The temperature impractical activities were conducted, however, during the observation period (three weeks experiments remained in a controlled environment in the science laboratory. For the experiments we used materials easily found in commerce, some recycled; students were organized into six teams, which improved the data collection, the maintenance of the experiments, the calculations of the percentages, and the producing of report. Many of these contents had not yet been studied in other disciplines, but were developed in the discipline of science, respecting prior knowledge and cognitive abilities. The use of experiments was effective for the construction of new knowledge and to develop skills necessary to start the search.

  17. GERMINATION STUDIES ON Tabebuia impetiginosa Mart. SEEDS

    Directory of Open Access Journals (Sweden)

    Edvaldo Aparecido Amaral da Silva

    2004-06-01

    Full Text Available Seed germination and seedling production of native forest tree species are an important step in ex situ conservation programs and in the reforestation with ecological purposes. Therefore, understanding seed germination and its regulation is mandatory for the complete success of the conservation programs and revegetation techniques. Thus, morphological studies, temperature requirements for seed germination and its control by gibberellins (GAs were studied in Tabebuia impetiginosa (“ipê-roxo” seeds. The best temperature for germination under constant light was 30oC. The imbibition of T. impetiginosa seeds followed the common triphasic pattern, with most of the seeds attaining phase II at 24 hours and phase III at 72 hours of imbibition. Visible germination, as radicle elongation, started at 30 hours in water-imbibed seeds and at 24 hours in GA-imbibed seeds. Seeds imbibed in Paclobutrazol, an inhibitor of GA biosynthesis, failed to germinate. However, application of exogenous gibberellins overcame inhibition and allowed germination, suggesting that GAs are regulators of Tabebuia impetiginosa seed germination. The results suggested that germination in Tabebuia impetiginosa seeds is controlled by elongation of the radicle and gibberellins may play an important role in regulating it. The possible role of gibberellins is discussed.

  18. Growth hormone induces multiplication of the slowly cycling germinal cells of the rat tibial growth plate.

    Science.gov (United States)

    Ohlsson, C; Nilsson, A; Isaksson, O; Lindahl, A

    1992-10-15

    To study the effect of locally infused growth hormone (GH) or insulin-like growth factor I(IGF-I) on slowly cycling cells in the germinal cell layer of the tibial growth plate, osmotic minipumps delivering 14.3 microCi of [3H]thymidine per day were implanted s.c. into hypophysectomized rats, and GH (1 microgram) or IGF-I (10 micrograms) was injected daily through a cannula implanted in the proximal tibia. The opposite leg served as a control. After 12 days of treatment, the osmotic minipumps were removed, and three rats in each group were given GH (20 micrograms/day, s.c.) for an additional 14 days to chase the labeled cells out of the proliferative layers. Labeled cells remained in the germinal layer, in the perichondrial ring, and on the surface of the articular cartilage close to the epiphyseal plate. GH administered together with labeled thymidine significantly increased the number of labeled cells in the germinal cell layer compared to that in the control leg (ratio = 1.95 +/- 0.13), whereas IGF-I showed no stimulatory effect (ratio = 0.96 +/- 0.04). Therefore GH but not IGF-I stimulates the multiplication of the slowly cycling (label-retaining) cells in the germinal layer of the epiphyseal plate. IGF-I acts only on the proliferation of the resulting chondrocytes.

  19. Identification of embryo proteins associated with seed germination and seedling establishment in germinating rice seeds.

    Science.gov (United States)

    Liu, Shu-Jun; Xu, Heng-Heng; Wang, Wei-Qing; Li, Ni; Wang, Wei-Ping; Lu, Zhuang; Møller, Ian Max; Song, Song-Quan

    2016-06-01

    Seed germination is a critical phase in the plant life cycle, but the mechanism of seed germination is still poorly understood. In the present study, rice (Oryza sativa L. cv. Peiai 64S) seeds were sampled individually when they reached different germination stages, quiescent, germinated sensu stricto, germinated completely and seedling, and were used to study the changes in the embryo proteome. A total of 88 protein spots showed a significant change in abundance during germination in water, and the results showed an activation of metabolic processes. Cell division, cell wall synthesis, and secondary metabolism were activated at late seed germination and during preparation for subsequent seedling establishment. Cycloheximide (CHX) at 70μM inhibited seedling establishment without an apparent negative effect on seed germination, while CHX at 500μM completely blocked seed germination. We used this observation to identify the potentially important proteins involved in seed germination (coleoptile protrusion) and seedling establishment (coleoptile and radicle protrusion). Twenty-six protein spots, mainly associated with sugar/polysaccharide metabolism and energy production, showed a significant difference in abundance during seed germination. Forty-nine protein spots, mainly involved in cell wall biosynthesis, proteolysis as well as cell defense and rescue, were required for seedling establishment. The results help improve our understanding of the key events (proteins) involved in germination and seedling development.

  20. Trematode reproduction in the molluscan host: an ultrastructural study of the germinal mass in the rediae of Himasthla elongata (Mehlis, 1831) (Digenea: Echinostomatidae).

    Science.gov (United States)

    Podvyaznaya, Irina M; Galaktionov, Kirill V

    2014-03-01

    The germinal mass in Himasthla elongata rediae was studied in detail using transmission electron microscopy. It was shown to be a specialized reproductive organ consisting of germinal cells at various maturation stages, supporting cells and stem cells. The germinal mass also contains early cercarial embryos emerging as a result of cleavage division of mature germinal cells. The stem cells that give rise to germinal cells have heterochromatin-rich nuclei with distinct nucleoli and scarce cytoplasm containing mainly free ribosomes and few mitochondria. The differentiating germinal cells undergo a growth, which is accompanied by an emergence of annulate lamellae and the nuage in their cytoplasm, a noticeable development of RER and Golgi apparatus and an increase in the number of mitochondria. The mitochondria form a large group at one of the cell poles. During differentiation, the nucleus and nucleolus of the germinal cell enlarge while the chromatin becomes gradually less condensed. The supporting tissue of the germinal mass is made up of cells connected by septate junctions. These supporting cells are distinctly different in cellular shape and nuclear ultrastructure. Their outgrowths form a tight meshwork housing stem cells, germinal cells and early cercarial embryos. The cytoplasm of the supporting cells in the mesh area is separated into fine parallel layers by labyrinthine narrow cavities communicating with the intercellular space. The supporting tissue contains differentiating and degenerating cells which indicates its renewal. The results of this ultrastructural study lend support to the hypothesis that the germinal cells of digeneans are germ line cells.

  1. Modelling the effect of temperature on seed germination in some ...

    African Journals Online (AJOL)

    USER

    2010-03-01

    Mar 1, 2010 ... The prediction of germination percentage (GP) and germination speed (GS) of the seeds for some ... rate and the germination frequency alongside the incu- ..... Considering that there has been marked interest by many.

  2. Germination Time Dependence of Bioactive Compounds and Antioxidant Activity in Germinated Rough Rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Anuchita Moongngarm

    2011-01-01

    Full Text Available Problem statement: Germinated rice has been recognized as a functional food and its health benefits. However, most related studies were on germinated brown rice but our previous study indicated that germination of rough rice was an effective method to obtain high concentrations of bioactive compounds. Germination time is one of the most important factors affecting the level of biochemical compositions and antioxidant activity. Approach: Rough rice seeds were soaked in water for 2 days and germinated for four different days (1- 4 days. Total phenolic compounds, phytic acid, á-tocopherol, á- tocopherol, á-tocotrienol and á-oryzanol were investigated compared with those of ungerminated brown rice. The antioxidant activity of germinated rice was evaluated through four different methods, the 1, 1- Diphenyl-2-Picrylhydrazyl (DPPH free radical scavenging assay, hydroxyl radical scavenging activity, lipid peroxidation assay and linoleic acid emulsion system-thiocyanate method. Results: The results showed that the germination for 2 days or longer, after soaking, yielded significantly higher level of total phenolic, á-tocopherol, á-tocopherol, á-tocotrienol and á-oryzanol than those of ungerminated brown rice and soaked rice, whilst the concentration of phytic acid was reduced significantly when germination time was increased. The samples germinated for one day or longer also revealed greater antioxidant activity than those of ungerminated rice. Conclusion: The level of bioactive compounds and antioxidant activity of germinated rough rice were affected by germination time. Germination for 2 and 3 days was the optimum time for germination rough rice to obtain high concentration of bioactive compounds and high antioxidant activity. The germination process of rough rice could be a potential method to obtain functional germinated rice flour with high bioactive compounds and health beneficial properties and could be applied to produce

  3. Effect of Environmental Factors on Germination and Emergence of Invasive Rumex confertus in Central Europe

    Directory of Open Access Journals (Sweden)

    Jeremi Kołodziejek

    2015-01-01

    Full Text Available Rumex confertus is a biennial species native to Eastern Europe and Asia, where it thrives on meadow-steppes and glades in forest-steppe. This species has increased its range rapidly within central Europe, yet its biology is not well understood, which has led to poorly timed management. Effects of temperature, light, sodium chloride (NaCl, hydrogen ion concentration (pH, potassium nitrate (KNO3, and polyethylene glycol 6000 on seed germination were examined. Seedling emergence was examined for seeds sown at different depths in sand-filled pots. Seeds of R. confertus were nondormant at maturity. The germination percentage and rate of germination were significantly higher in light than in darkness. Secondary dormancy was induced in these seeds by 12 weeks of dark incubation at 4°C. The seeds of R. confertus undergo a seasonal dormancy cycle with deep dormancy in winter and early spring and a low level of dormancy in early autumn. Germination decreased as soil salinity increased. NO3- increased the percentage and rate of germination in the studied species. Decrease in seedling emergence from the seeds buried at >0.5 cm may be due to deficiency of light. From our experiments, we conclude that the weed R. confertus normally becomes established in vegetation gaps or due to disturbance of the uppermost soil layer during the growing season through the germination of seeds originating from a long-lived seed bank.

  4. External Otitis (Swimmer's Ear)

    Science.gov (United States)

    ... to Pneumococcal Vaccine Additional Content Medical News External Otitis (Swimmer's Ear) By Bradley W. Kesser, MD, Associate ... the Outer Ear Ear Blockages Ear Tumors External Otitis (Swimmer's Ear) Malignant External Otitis Perichondritis External otitis ...

  5. On the New Technology of Using Perlite for Insulation Layer of External Wall%谈外墙保温层利用珍珠岩的新工艺

    Institute of Scientific and Technical Information of China (English)

    曾笳

    2013-01-01

      建筑行业中资源消耗减量化、污染排放量最小化、废物再生资源化和无害化是今后发展的必然趋势。文章介绍了外墙保温技术的优点,探讨利用珍珠岩作为外墙保温层的新工艺的施工流程和施工要点,为该行业提供参考。%Resource consumption reduction, pollution emissions minimization, material regeneration and harmless, all of them in the construction industry are a certain trend in the future. The paper introduces the advantages of thermal insulation tech-nology in exterior wall, explores construction process and construction points of the new technology that use the perlite as the thermal insulation layer of external wall, providing some references for the field.

  6. Rapid and High Seed Germination and Large Soil Seed Bank of Senecio aquaticus in Managed Grassland

    Directory of Open Access Journals (Sweden)

    Matthias Suter

    2012-01-01

    Full Text Available Senecio aquaticus, regionally a Red List species in Europe, has become increasingly abundant in agricultural grassland of medium to high management intensity in Switzerland, Southern Germany, and Austria in recent years, where it is a threat for animal and human health due to its toxicity. In this study, we investigated the seed ecology of S. aquaticus to help protection of the species in relic populations while improving its control when abundant in managed grassland. Germination percentages of fresh ripe seeds of S. aquaticus were on average 68% in 2008, but only 45% in 2010, indicating yearly variation. Germination was generally fast: ten days after the onset of the tests, often more than 45% of all seeds had germinated. When covered with a soil layer of 5 mm, germination was only 16% compared to 63% in full light. Seeds buried in the soil for one and two years showed a germination of 78%, significantly higher than that of fresh ripe seeds, thus suggesting a stimulating effect of cold-wet stratification on germination and long seed survival in the soil. In grasslands with established populations of S. aquaticus, the number of germinable seeds of the species ranged from 361 to 1875 m-2 in topsoil (0–10 cm with an average of 1139 m-2. The large seed bank and the rapid and high germination of S. aquaticus suggest that allowing seed formation is important for its preservation in relic populations. With respect to agricultural grassland, strategies to control the species should initially target hindering seed production and dispersal.

  7. Influence of storage on the position of the germinal disc in the fertilized unincubated chicken egg.

    Science.gov (United States)

    Burkhardt, A; Meister, S; Bergmann, R; Koch, E

    2011-10-01

    The breeding of male layer chickens is currently considered to be highly uneconomical. In Germany alone, 40 to 50 million newly hatched male chickens were killed annually immediately after hatching. Therefore, it is necessary to find a method for sexing chickens early in the embryonic development, preferably before incubation. The genotypic sex of an egg can be determined using information found in the germinal disc, so knowledge of the exact position of the germinal disc is essential for further sexing, or for other actions such as the in ovo injection of agents. Previous studies have shown that the germinal disc is located somewhere on top of the yolk. However, no studies have yet been performed that investigate the influence of time spent in horizontal storage on the position of the germinal disc. Magnetic resonance imaging was chosen to determine this influence on the position of the germinal disc. It was found that eggs placed horizontally for long periods of time before scanning had significant changes in the positions of their germinal discs compared with those of eggs scanned minutes after positioning. The position of the germinal disc in eggs, minutes after horizontal positioning, deviated 14.7 ± 0.6 mm from the maximum vertical plane of the egg (zero position) in the z-direction; eggs scanned after 96 h of horizontal positioning showed a deviation of only 4.9 ± 1.6 mm. The x-axis also exhibited changes in the position of the germinal disc over time. Immediately after horizontal positioning, the eggs showed a deviation of 0.4 ± 0.4 mm in the x-direction, whereas the deviation after 96 h was 2.9 ± 0.5 mm. These results show that horizontal positioning of the egg hours before the measurement is necessary.

  8. Gibberellins regulate seed germination in tomato by endosperm weakening: a study with gibberellin-deficient mutants.

    Science.gov (United States)

    Groot, S P; Karssen, C M

    1987-08-01

    The germination of seeds of tomato [Lycopersicon esculentum (L.) Mill.] cv. Moneymaker has been compared with that of seeds of the gibberellin-deficient dwarf-mutant line ga-1, induced in the same genetic background. Germination of tomato seeds was absolutely dependent on the presence of either endogenous or exogenous gibberellins (GAs). Gibberellin A4+7 was 1000-fold more active than commercial gibberellic acid in inducing germination of the ga-1 seeds. Red light, a preincubation at 2°C, and ethylene did not stimulate germination of ga-1 seeds in the absence of GA4+7; however, fusicoccin did stimulate germination independently. Removal of the endosperm and testa layers opposite the radicle tip caused germination of ga-1 seeds in water. The seedlings and plants that develop from the detipped ga-1 seeds exhibited the extreme dwarfy phenotype that is normal to this genotype. Measurements of the mechanical resistance of the surrounding layers showed that the major action of GAs was directed to the weakening of the endosperm cells around the radicle tip. In wild-type seeds this weakening occurred in water before radicle protrusion. In ga-1 seeds a similar event was dependent on GA4+7, while fusicoccin also had some activity. Simultaneous incubation of de-embryonated endosperms and isolated axes showed that wild-type embryos contain and endosperm-weakening factor that is absent in ga-1 axes and is probably a GA. Thus, an endogenous GA facilitates germination in tomato seeds by weakening the mechanical restraint of the endosperm cells to permit radicle protrusion.

  9. QTL analysis of rice low temperature germinability

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A double haploid population, derived from anther culture of F1 hybrid between a typical indica and a japonica (ZYQ8/JX17), has been used to investigate the low temperature germinability (LTG) at 15C. The low temperature germinability of two parents was significantly different.In 6-11 d, the germination percentage of ZYQ8 was higher than that of JX17. In 12-16 d, the germination percentage of JX17 was higher than that of ZYQ8. The quantitative trait loci (QTLs) of every day for low temperature germinability have been mapped based on a molecular linkage map constructed from this population. In 8-11 d, qLTG-9 was identiffed in C397B-RZ617B on chromosome 9, the additive effect was positive, showing that the allele from JX17 could increase low temperature germinability. In 12-16 d, qLTG4 was mapped between RG908 and CT563 on chromosome 4,the additive effect was negative, showing that the allele from ZYQ8 could increase low temperature germinability. These two QTLs were detected at different stages, showing the complexity of the mechanism of iow temperature germinability.

  10. Seed germination behavior of swallow wort

    Directory of Open Access Journals (Sweden)

    amir hosein pahlavani

    2009-06-01

    Full Text Available The exotic plant, Swallow- wort, a twining perennial of the Milkweed family, has become increasingly invasive in some place of Iran, especially orchards. Increased knowledge of wort germination biology would facilitate development of an optimum control program. Germination of Swallow wort seeds as affected by environmental factors was studied under controlled-environment growth chamber conditions. The following studies were conducted in plant Pests & Diseases Research Institute during the years 2003-4: 1- Effect of constant temperature on germination that including 10, 15, 18, 20, 25, 30, 35 and 40˚C; 2- Effect of light on constant germination; 3- Effect of temperature fluctuations on seed germination: 15/7, 20/12, 25/17 and 30/22˚C. All experiments were conducted with 8 replications. Swallow wort seeds showed no dormancy when detachment from mother plant. Seed germination was strongly influenced by temperature. Light did not play a crucial role on seed germination of this weed. Therefore Swallow wort seeds were not photoblastic and temperature fluctuations did not increase seed germination of Swallow wort. The above characteristics are very important in making swallowwort an invasive weed. Having precise information of these traits enables us to a better management and control of this troublesome weed.

  11. Evidence for osmotic regulation of hydrolytic enzyme production in germinating barley seeds.

    Science.gov (United States)

    Jones, R L; Armstrong, J E

    1971-08-01

    alpha-Amylase levels in intact seeds of barley (Hordeum vulgare L. cv. Himalaya) reach a maximum at 3 to 4 days of germination while gibberellin levels continue to increase beyond 6 days of germination. In contrast to its effect on half seeds, gibberellic acid does not increase the total amount of alpha-amylase produced in germinating seeds. The inability of gibberellic acid to stimulate alpha-amylase production is not related to its availability; rather, evidence suggests that a factor(s) in whole seeds prevents further enhancement of alpha-amylase formation and accumulation. Hydrolysis products accumulate in the subaleurone space of the endosperm of germinating seeds up to concentrations of 570 milliosmolar. Chromatography of these hydrolysis products indicate the presence of maltose and glucose. Calculations based on reducing sugar determinations show that glucose accounts for as much as 57% of the solutes present in the endosperm fluid. Both maltose and glucose in the range of 0.2 to 0.4 M effectively inhibit the production of alpha-amylase by isolated barley aleurone layers. This inhibition is quantitatively similar to that brought about by solutions of polyethylene glycol and mannitol. On the basis of these data we propose that hydrolysis products which accumulate in the starchy endosperm of germinating seeds function to regulate the production of hydrolytic enzymes by the aleurone layer.

  12. Spatial and temporal regulation of DNA fragmentation in the aleurone of germinating barley

    NARCIS (Netherlands)

    Wang, M.; Oppedijk, B.J.; Caspers, M.P.M.; Lamers, G.E.M.; Boot, M.J.; Geerlings, D.N.G.; Bakhuizen, B.; Meijer, A.H.; Duijn, B. van

    1998-01-01

    During germination of barley grains, the appearance of DNA fragmentation started in aleurone cells near the embryo and extended to the distal end in a time-dependent manner. DNA fragmentation was demonstrated to occur only after the expression of α-amylase mRNA in the aleurone layer. In addition, ce

  13. Spatial and temporal regulation of DNA fragmentation in the aleurone of germinating barley

    NARCIS (Netherlands)

    Wang, M.; Oppedijk, B.J.; Caspers, M.P.M.; Lamers, G.E.M.; Boot, M.J.; Geerlings, D.N.G.; Bakhuizen, B.; Meijer, A.H.; Duijn, B. van

    1998-01-01

    During germination of barley grains, the appearance of DNA fragmentation started in aleurone cells near the embryo and extended to the distal end in a time-dependent manner. DNA fragmentation was demonstrated to occur only after the expression of α-amylase mRNA in the aleurone layer. In addition, ce

  14. [Metabolic control of seed germination].

    Science.gov (United States)

    Catusse, Julie; Strub, Jean-Marc; Job, Claudette; Van Dorsselaer, Alain; Job, Dominique

    2008-01-01

    We have used proteomics to better characterize germination and early seedling vigor in sugarbeet. Our strategy includes (1) construction of proteome reference maps for dry and germinating seeds of a high-vigor reference seed lot; (2) investigation of the specific tissue accumulation of proteins (root, cotyledon, perisperm); (3) investigation of changes in protein expression profiles detected in the reference seed lot subjected to different vigor-modifying treatments, e.g. aging and/or priming. More than 1 000 sugarbeet seed proteins have been identified by LC/MS-MS mass spectrometry (albumins, globulins and glutelins have been analyzed separately). Due to the conservation of protein sequences and the quality of MS sequencing (more than 10 000 peptide sequences have been obtained), the success rate of protein identification was on the average of 80%. This is to our knowledge the best detailed proteome analysis ever carried out in seeds. The data allowed us to build a detailed metabolic chart of the sugarbeet seed, generating new insights into the molecular mechanisms determining the development of a new seedling. Also, the proteome of a seed-storage tissue as the perisperm is described for the first time.

  15. Changes of Limiting Dextrinase in Germinating Process of Malting Barley

    Institute of Scientific and Technical Information of China (English)

    LIANG Xiu-mei; LI Fen; WANG Hong-zhen; WANG Xing-zhi

    2002-01-01

    Based on five different species of barley, the foot layer analytic method was used to examine the activity and heat-resistance of the limiting dextrinase. The study was conducted on the dynamic changes of several types of the dextrinase in barley germinating process, the effect of temperature on the dextrinase and the divergence of dextrinase in different barley variety. The probability of the dextrinase that as reference index is used for screening and evaluating beer barley was discussed. The importance of dextrinase in brewing and its significant function was also discussed.

  16. Genes involved in ethylene and gibberellins metabolism are required for endosperm-limited germination of Sisymbrium officinale L. seeds: germination in Sisymbrium officinale L. seeds.

    Science.gov (United States)

    Iglesias-Fernández, Raquel; Matilla, Angel J

    2010-02-01

    The rupture of the seed coat and that of the endosperm were found to be two sequential events in the germination of Sisymbrium officinale L. seeds, and radicle protrusion did not occur exactly in the micropylar area but in the neighboring zone. The germination patterns were similar both in the presence of gibberellins (GA(4+7)) and in presence of ethrel. The analysis of genes involved in GAs synthesis and breakdown demonstrated that (1) SoGA2ox6 expression peaked just prior to radicle protrusion (20-22 h), while SoGA3ox2 and SoGA20ox2 expression was high at early imbibition (6 h) diminishing sharply thereafter; (2) the accumulation of SoGA20ox2 transcript was strongly inhibited by paclobutrazol (PB) as well as by inhibitors of ET synthesis and signaling (IESS) early after imbibition (6 h), while SoGA3ox2 and SoGA2ox6 expression was slowly depressed as germination progressed; (3) ethrel and GA(4+7) positively or negatively affected expression of SoGA3ox2, SoGA20ox2, and SoGA2ox6, depending on the germination period studied. Regarding genes involved in ET synthesis, our results showed that SoACS7 was expressed, just prior to radicle emergence while SoACO2 expression slowly increased as germination progressed. Both genes were strongly inhibited by PB but were almost unaffected by externally added ethrel or GA(4+7). These results suggest that GAs are more important than ET during the early stages of imbibition, while ET is more important at the late phases of germination of S. officinale L. seeds.

  17. Efeito de cascas de café e de arroz dispostas nas camadas do solo sobre a germinação e o crescimento inicial do caruru-de-mancha Allelopathic effect of coffee and rice husks arranged in soil layers on the germination and initial growth of Amaranthus viridis

    Directory of Open Access Journals (Sweden)

    J.C.F. Santos

    2001-08-01

    Full Text Available Estudos dos efeitos dos resíduos de plantas pela utilização de coberturas mortas no controle das plantas daninhas têm apresentado dificuldade de determinar a diferenciação entre alelopatia e competição. Atualmente, muitas pesquisas têm se referido a critérios que propõem evidência à alelopatia. Este trabalho em casa de vegetação visou determinar os efeitos alelopáticos proporcionados pelas cascas de café e de arroz sobre o caruru-de-mancha, por meio das disposições desses resíduos nas camadas do solo. O delineamento experimental foi o de blocos casualizados, com os tratamentos em quatro repetições e organizados num esquema fatorial (3x3, sendo cascas de café e de arroz e vermiculita expandida como um fator e suas disposições, com resíduos depositados no topo, incorporados na superfície e incorporados no fundo, como segundo fator. Como testemunha foi usado um tratamento adicional sem cobertura. De modo geral, resíduos de cascas proporcionaram inibição da germinação e estímulo ao crescimento do caruru-de-mancha. A casca de arroz proporcionou menor índice de velocidade de emergência e germinação de sementes do que a casca de café. A casca de café depositada no topo proporcionou maior crescimento e maior peso da matéria seca do caruru-de-mancha, seguido pela mesma casca incorporada na superfície do solo.Studies of plant residue effects involving mulches to control weeds in perennial crops are difficult to carry out due to the need to differentiate between allelopathy and competition. Many researches, nowadays, refer to criteria proving allelopathy. This work was established under greenhouse conditions to determine the allelopathic effects of coffee and rice husks on Amaranthus viridis through their arrangements in soil layers. The experimental design was a randomized block with four replications, arranged in a 3 x 3 factorial scheme, with coffee and rice husks and expanded vermiculite being one factor and

  18. Integrating Building Functions into Massive External Walls

    Directory of Open Access Journals (Sweden)

    Ahmed Hisham Hafez

    2016-05-01

    Full Text Available Well into the twentieth century, brick and stone were the materials used. Bricklaying and stonemasonry were the construction technologies employed for the exterior walls of virtually all major structures. However, with the rise in quality of life, the massive walls alone became incapable of fulfilling all the developed needs. Adjacent systems and layers had then to be attached to the massive layer. Nowadays, the external wall is usually composed of a layered construction. Each external wall function is usually represented by a separate layer or system. The massive layer of the wall is usually responsible for the load-bearing function.Traditional massive external walls vary in terms of their external appearance, their composition and attached layers. However, their design and construction process is usually a repeated process. It is a linear process where each discipline is concerned with a separate layer or system. These disciplines usually take their tasks away and bring them back to be re-integrated in a layered manner. New massive technologies with additional function have recently become available.Such technologies can provide the external wall with other functions in addition to its load-bearing function. The purpose of this research is to map the changes required to the traditional design and construction process when massive technologies with additional function are applied in external walls. Moreover, the research aims at assessing the performance of massive solutions with additional function when compared to traditional solutions in two different contexts, the Netherlands and Egypt.Through the analysis of different additional function technologies in external walls, a guidance scheme for different stakeholders is generated. It shows the expected process changes as related to the product level and customization level. Moreover, the research concludes that the performance of additional insulating technologies, and specifically Autoclaved

  19. Maximizing seed germination in two Acacia species

    Institute of Scientific and Technical Information of China (English)

    Akram Kiani Abari; Mohammad Hoseini Nasr; Mohammad Hodjati; Dariush Bayat; Morteza Radmehr

    2012-01-01

    Revegetation of disturbed land,particularly in arid environment,is often hindered by low seedling establishment.Information on seed biology and germination cues of valuable species is lacking.We investigated seed germination of two Acacia species (Acacia tortilis (Forsk.) Hayne and Acacia oerfota (Forssk) schweinf),required for nitrogen fixation and rehabilitation of arid and semi-arid areas.(four pre-germination seed treatments were applied in order to find the best treatment in germinating acacia species.The medium was L2 and three replicates were used.Seeds pre-treated with sand paper and also with H2SO4 and then H2O2 had the highest germination percentage in both species.The lowest germination percentage resulted from soaking seeds in water for 48 h followed by soaking in H2SO4 for A.oerfota and from soaking in water for 24 h for A.tortilis.Because the use of sand paper is difficult and time consuming,we recommend pre-treatment of A.tortilis and A.oerfota seeds with H2SO4 and H2O2 before planting.Our study results are significant for conservation agencies with an interest in optimizing germination in arid zones for rehabilitation and reforestation.

  20. Spontaneous germinal centers and autoimmunity.

    Science.gov (United States)

    Domeier, Phillip P; Schell, Stephanie L; Rahman, Ziaur S M

    2017-02-01

    Germinal centers (GCs) are dynamic microenvironments that form in the secondary lymphoid organs and generate somatically mutated high-affinity antibodies necessary to establish an effective humoral immune response. Tight regulation of GC responses is critical for maintaining self-tolerance. GCs can arise in the absence of purposeful immunization or overt infection (called spontaneous GCs, Spt-GCs). In autoimmune-prone mice and patients with autoimmune disease, aberrant regulation of Spt-GCs is thought to promote the development of somatically mutated pathogenic autoantibodies and the subsequent development of autoimmunity. The mechanisms that control the formation of Spt-GCs and promote systemic autoimmune diseases remain an open question and the focus of ongoing studies. Here, we discuss the most current studies on the role of Spt-GCs in autoimmunity.

  1. Hydration, sporoderm breaking and germination of Cupressus arizonica pollen.

    Science.gov (United States)

    Chichiriccò, G; Spanò, L; Torraca, G; Tartarini, A

    2009-05-01

    In vitro and in vivo rehydration and germination in Cupressus arizonica pollen were examined using light and scanning electron microscopy. Shed pollen has 12.6% water content, which reduced to 8.2% after dispersal, and this latter pollen survived for some months at room temperature and for years at -10 degrees C. Rehydration requires breaking of the sporoderm walls and depends on the composition and pH of the rehydration medium. Acidity restrains the breakage, while alkalinity promotes it. Pollen division follows exine shedding and requires the persistence of the mucilaginous layer; hence, pH values countering these outcomes prevent division. Division results in a large and a small cell separated by a callosic wall. A pollen tube develops from the innermost intine of the large cell, which is callosic, and extends into the mucilaginous middle intine. The percentage germination never exceeded 17% in all tested media. In vivo, pollen rehydrates and casts off the exine in the micropylar drop. Drop withdrawal brings pollen to the apical nucellar cells that degenerate in the meantime, and it leaves a deposit on the surface of the micropylar canal. After contaction of the nucellar cells, the pollen flattens and its mucilaginous layer shrinks and disappears. This occurs simultaneously with sealing of the micropylar canal. During this time, pollen divides asymmetrically without the callosic wall, and the larger cell develops a tube in the interface with the nucellus. Only some pollen grains accomplish adhesion to the nucellus and germinate. The in vitro and in vivo developmental stages are discussed.

  2. Photocontrol of germination in Amaranthus caudatus.

    Science.gov (United States)

    Kendrick, R E; Frankland, B

    1969-12-01

    Germination of Amaranthus caudatus is inhibited by light, far-red being the most effective part of the spectrum. At temperatures of 25° and below there is a low final germination percentage under continuous far-red whereas above 25° there is only a delaying effect. In the presence of a saturating concentration of gibberellic acid (GA3) at 25° seeds germinate under continuous far-red although they are delayed. At 25° seeds exposed to 48 hr far-red fail to germinate when transferred to darkness. This induced dormancy can be broken by a single short exposure to red light given at any time after the far-red illumination. This effect of short red can be reversed by a subsequent short period of far-red indicating that the seeds are phytochrome controlled. Although most seeds have escaped from the reversing effect of short far-red after an intervening dark period of 5 hours, germination is greatly reduced by continuous far-red at this time. Results of exposing seeds to varying periods of far-red before and after dark imbibition are interpreted in terms of a continual production of phytochrome in its active P fr form and a requirement for P fr action over a long period of time. Effects of intermittent and continuous low intensity far-red on the inhibition of germination provides further evidence for a low energy photoreaction involving phytochrome. Effects on Germination Index of continuous illumination with various light sources maintaining different P fr /P total ratios have been investigated. The results suggest that the proportion of phytochrome in the P fr form is the most important factor in the regulation of germination. A scheme for the phytochrome control of germination in Amaranthus caudatus is presented and possible explanations for the dependence on P fr /P total ratio are discussed.

  3. 7 CFR 201.54 - Number of seeds for germination.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Number of seeds for germination. 201.54 Section 201.54... REGULATIONS Germination Tests in the Administration of the Act § 201.54 Number of seeds for germination. At least 400 seeds shall be tested for germination; except that in mixtures, 200 seeds of each of...

  4. Dormancy, germination and emergence of weed seeds, with emphasis on the influence of light : results of a literature survey

    NARCIS (Netherlands)

    Riemens, M.M.; Scheepens, P.C.; Weide, van der R.Y.

    2004-01-01

    This note reports the results of an inventory study about the influence of the external factors temperature, light, nitrate, gaseous environment of seeds and moisture on the dormancy, germination and emergence of weed seeds. The inventory was made as a guideline for research aiming at the developmen

  5. Dormancy, germination and emergence of weed seeds, with emphasis on the influence of light : results of a literature survey

    NARCIS (Netherlands)

    Riemens, M.M.; Scheepens, P.C.; Weide, van der R.Y.

    2004-01-01

    This note reports the results of an inventory study about the influence of the external factors temperature, light, nitrate, gaseous environment of seeds and moisture on the dormancy, germination and emergence of weed seeds. The inventory was made as a guideline for research aiming at the developmen

  6. Pulling the trigger: the mechanism of bacterial spore germination.

    Science.gov (United States)

    Foster, S J; Johnstone, K

    1990-01-01

    In spite of displaying the most extreme dormancy and resistance properties known among living systems, bacterial endospores retain an alert environment-sensing mechanism that can respond within seconds to the presence of specific germinants. This germination response is triggered in the absence of both germinant and germinant-stimulated metabolism. Genes coding for components of the sensing mechanism in spores of Bacillus subtilis have been cloned and sequenced. However, the molecular mechanism whereby these receptors interact with germinants to initiate the germination response is unknown. Recent evidence has suggested that in spores of Bacillus megaterium KM, proteolytic activation of an autolytic enzyme constitutes part of the germination trigger reaction.

  7. Phytochrome and Seed Germination. I. Temperature Dependence and Relative P(FR) Levels in the Germination of Dark-germinating Tomato Seeds.

    Science.gov (United States)

    Mancinelli, A L; Yaniv, Z; Smith, P

    1967-03-01

    Germination of the dark-germinating seeds of 3 varieties of tomato is controlled by the phytochrome system. Germination is inhibited by far red radiation and repromoted by red applied after far red. At low temperatures, 17 to 20 degrees , a single, low energy far red irradiation is sufficient to inhibit germination in all 3 varieties. At higher temperatures far red is less effective in the inhibition of the germination of the tomato seeds. The phytochrome fraction present as P(FR) in the dark-germinating seeds of the Ace variety is about 40% of the total phytochrome present.

  8. Spore germination and germinant receptor genes in wild strains of Bacillus subtilis.

    Science.gov (United States)

    Alzahrani, O M; Moir, A

    2014-09-01

    To compare the germination of laboratory and wild strains of Bacillus subtilis. The spore germination of B. subtilis 168 (subsp. subtilis) was compared with that of the laboratory strain W23 (subsp. spizizenii) and desert-sourced isolates, including one member of subsp. subtilis (RO-NN-1), strains TU-B-10, RO-E-2, N10 and DV1-B-1, (all subsp. spizizenii), the B. mojavensis strain RO-H-1 and a B. subtilis natto strain. All germinated in L-alanine, although some were slower, and some 10-fold less sensitive to germinant. All germinated in calcium dipicolinate (CaDPA). Germination in asparagine, glucose, fructose + KCl was slow and incomplete in many of the strains, and decoating RO-NN-1 and W23 spores did not restore germination rates. Comparing the sequences of B. subtilis strains 168, RO-NN-1, W23, TU-B-10 and DV1-B-1, the operons encoding GerA, B and K germinant receptors were intact, although the two additional operons yndDEF and yfkQRST had suffered deletions or were absent in several spizizenii strains. Wild strains possess an efficient germination machinery for L-alanine germination. AGFK germination is often less efficient, the gerB genes more diverged, and the two germinant receptor operons of unknown function have been lost from the genome in many subsp. spizizenii strains. The two major subspecies of B. subtilis have conserved GerA receptor function, confirming its importance, at least in the natural environments of these strains. © 2014 The Society for Applied Microbiology.

  9. High dilutions of Magonia pubescens hidrogel affect germination variables in Sorghum bicolor L. Moench

    Directory of Open Access Journals (Sweden)

    Carolina Bertuzzi Pereira

    2011-09-01

    Full Text Available Introduction: In science homeopathic diseases or physiological disorders are not considered just a result of abiotic and biotic factors, but rather a consequence of loss of organic system homeostasis. Homeopathic science is currently being used efficiently in the control of plagues[1], plant diseases[2], in the increase of medicinal plants’ active principles[3] and in plant metabolism[4,5]. Although actual results, both in the academic and field-level, very little is known about physiological mechanisms action of homeopathic medicine on germination process[6]. This work aims to study the effect of M. pubescens hydrogel, on some physiological variables of sorghum germination (Sorghum bicolor L. Moench. Material and methods: The experiment was conducted at Homeopathy and Plant Physiology of Biology Department at UEM in the period from 04/05/06 to 30/12/06. M. pubescens (tingui seeds were obtained from the region of Montes Claros - Minas Gerais. The M. pubescens hidrogel was obtained from the external centrals wrappers of 4 dry seeds, after they have been disposed in petri dishes with distilled water for a period of 36 hours of soaking (25oC. The hydrogel mother tincture was prepared according to Manual of Technical Standards for Homeopathic Drugstore[7] 3rd ed (2003, in the proportion of a hidrogel part (5g to ten parts (50g of absolute alcohol 70% and stored in a glass amber (capped and protected from light. After 15 days of maceration, the solution was filtered and after 48h at rest, the mother tincture was considered ready for use. The dilution 1cH (Centesimal Hahnemannian was obtained by adding 0.2 ml of the mother tincture in 19.8 ml of distilled water (1/100 and sucussioned 100 times (33 sucussions s-1 by mechanical arm dynamizer with automatic stop (Model Denise 50 - AUTIC. The subsequent dilutions (2cH to 30cH were obtained from the same procedure, starting from the dilution 1cH. Bioassay: In petri dish containing 15

  10. Workshop report: modeling the molecular mechanism of bacterial spore germination and elucidating reasons for germination heterogeneity.

    Science.gov (United States)

    Indest, Karl J; Buchholz, Wallace G; Faeder, Jim R; Setlow, Peter

    2009-08-01

    Over the course of 2 days, top researchers in the fields of bacterial spore biology and computational biology discussed approaches to determine the cause of spore germination heterogeneity. Biological and mathematical data gaps were identified, and experimental approaches and computational strategies for modeling spore germination were presented and evaluated. As a result of these interactions, future research directions were defined, the outcome of which should result in a robust model to help define the molecular mechanism(s) of spore germination. Mechanistic understanding of germination will be instrumental for developing novel sterilization, treatment, and decontamination strategies to mitigate threats posed by spores.

  11. Bioethanol production from germinated grain by inherent enzymes

    OpenAIRE

    Kádár, Zsófia; Christensen, Anne Deen; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

    2009-01-01

    The malting in brewing process develops enzymes that are required to hydrolyze the complex starch in grain into simple fermentable sugars. These proceed the three following steps: Steeping encourages germination to start, germination prepares the conversion of the starch to sugars, and kilning stops the germination. In this study, a method for bioethanol production from rye grain was developed by utilizing the inherent amylase activity from germination of the seed. Grain germination was pe...

  12. Bacterial spore germination and protein mobility.

    Science.gov (United States)

    Moir, Anne

    2003-10-01

    Fluorescence recovery after photobleaching (FRAP) of green fluorescent protein (GFP) has been used to report on protein mobility in single spores. Proteins found in dormant Bacillus spores are not mobile; however, mobility is restored when germination occurs and the core rehydrates. Spores of a cwlD mutant, in which the cortex is resistant to hydrolysis, are able to complete the earliest stages of germination in response to a specific germinant stimulus; in these circumstances, the protein in the spore remains immobile. Therefore, the earliest stages of spore germination, including loss of resistance to extreme heat and the complete release of the spore component dipicolinic acid, are achieved without the restoration of protein mobility.

  13. Germination, growth and physiological responses of Senegalia ...

    African Journals Online (AJOL)

    Dioumacor FALL

    2016-09-14

    Sep 14, 2016 ... photosynthesis such as enzymes, chlorophylls, and carotenoids are also .... The reverse transcription (RT) reactions were performed at 42°C for ..... light on germination of invasive Prosopis juliflora (Sw.) D.C. J. Arid. Environ.

  14. (edta) on the germination of tomato

    African Journals Online (AJOL)

    Dr A.B.Ahmed

    has been found to reduced salinity stress on germination of two species of pepper .... osmotic component, with the ionic component, involving accumulation of Na and Cl .... Salt and drought stress signal transduction in plants. Annal Review of.

  15. Germination of Afrocarpus usambarensis and Podocarpus ...

    African Journals Online (AJOL)

    ACSS

    Uganda Journal of Agricultural Sciences by National Agricultural Research Organisation ..... Germination capacity of A. usambarensis and P. milanjianus seeds ..... properly managed to provide seeds. ... for the permission to carry out the study.

  16. Programmed cell death (PCD an essential process of cereal seed development and germination

    Directory of Open Access Journals (Sweden)

    Fernando eDomínguez

    2014-07-01

    Full Text Available The life cycle of cereal seeds can be divided into two phases, development and germination, separated by a quiescent period. Seed development and germination require the growth and differentiation of new tissues, but also the ordered disappearance of cells, which takes place by a process of programmed cell death (PCD. For this reason, cereal seeds have become excellent model systems for the study of developmental PCD in plants. At early stages of seed development, maternal tissues such as the nucellus, the pericarp and the nucellar projections undergo a progressive degeneration by PCD, which allows the remobilization of their cellular contents for nourishing new filial tissues such as the embryo and the endosperm. At a later stage, during seed maturation, the endosperm undergoes PCD, but these cells remain intact in the mature grain and their contents will not be remobilized until germination. Thus, the only tissues that remain alive when seed development is completed are the embryo axis, the scutellum and the aleurone layer. In germinating seeds, both the scutellum and the aleurone layer play essential roles in producing the hydrolytic enzymes for the mobilization of the storage compounds of the starchy endosperm, which serve to support early seedling growth. Once this function is completed, scutellum and aleurone cells undergo PCD; their contents being used to support the growth of the germinated embryo. PCD occurs with tightly controlled spatial-temporal patterns allowing coordinated fluxes of nutrients between the different seed tissues. In this review, we will summarize the current knowledge of the tissues undergoing PCD in developing and germinating cereal seeds, focussing on the biochemical features of the process. The effect of hormones and redox regulation on PCD control will be discussed.

  17. Expression of the gene encoding the PR-like protein PRms in germinating maize embryos.

    Science.gov (United States)

    Casacuberta, J M; Raventós, D; Puigdoménech, P; San Segundo, B

    1992-07-01

    The PRms protein is a pathogenesis-related (PR)-like protein whose mRNA accumulates during germination of maize seeds. Expression of the PRms gene is induced after infection of maize seeds with the fungus Fusarium moniliforme. To further our investigations on the expression of the PRms gene we examined the accumulation of PRms mRNA in different tissues of maize seedlings infected with F. moniliforme and studied the effect of fungal elicitors, the mycotoxin moniliformin, the hormone gibberellic acid, and specific chemical agents. Our results indicate that fungal infection, and treatment either with fungal elicitors or with moniliformin, a mycotoxin produced by F. moniliforme, increase the steady-state level of PRms mRNA. PRms mRNA accumulation is also stimulated by the application of the hormone gibberellic acid or by treatment with silver nitrate, whereas acetylsalicylic acid has no effect. In situ RNA hybridization in isolated germinating embryo sections demonstrates that the PRms gene is expressed in the scutellum, particularly in a group of inner cells, and in the epithelium lying at the interface of the scutellum and the endosperm. The pattern of expression of the PRms gene closely resembles that found for hydrolytic enzymes, being confined to the scutellum and the aleurone layer of the germinating maize seed. Our results suggest that the PRms protein has a function during the normal process of seed germination that has become adapted to serve among the defence mechanisms induced in response to pathogens during maize seed germination.

  18. Oxygen dependency of germinating Brassica seeds

    Science.gov (United States)

    Park, Myoung Ryoul; Hasenstein, Karl H.

    2016-02-01

    Establishing plants in space, Moon or Mars requires adaptation to altered conditions, including reduced pressure and composition of atmospheres. To determine the oxygen requirements for seed germination, we imbibed Brassica rapa seeds under varying oxygen concentrations and profiled the transcription patterns of genes related to early metabolism such as starch degradation, glycolysis, and fermentation. We also analyzed the activity of lactate dehydrogenase (LDH) and alcohol dehydrogenase (ADH), and measured starch degradation. Partial oxygen pressure (pO2) greater than 10% resulted in normal germination (i.e., protrusion of radicle about 18 hours after imbibition) but lower pO2 delayed and reduced germination. Imbibition in an oxygen-free atmosphere for three days resulted in no germination but subsequent transfer to air initiated germination in 75% of the seeds and the root growth rate was transiently greater than in roots germinated under ambient pO2. In hypoxic seeds soluble sugars degraded faster but the content of starch after 24 h was higher than at ambient oxygen. Transcription of genes related to starch degradation, α-amylase (AMY) and Sucrose Synthase (SUS), was higher under ambient O2 than under hypoxia. Glycolysis and fermentation pathway-related genes, glucose phosphate isomerase (GPI), 6-phosphofructokinase (PFK), fructose 1,6-bisphosphate aldolase (ALD), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate decarboxylase (PDC), LDH, and ADH, were induced by low pO2. The activity of LDH and ADH was the highest in anoxic seeds. Germination under low O2 conditions initiated ethanolic fermentation. Therefore, sufficient oxygen availability is important for germination before photosynthesis provides necessary oxygen and the determination of an oxygen carrying capacity is important for uniform growth in space conditions.

  19. GERMINATION ASSESSMENT ON DIFFERENT OSMOTIC POTENTIALS AND SEED AND SEEDLING MORPHOLOGIC CHARACTERIZATION OF THE Ateleia glazioviana BAILL (TIMBO

    Directory of Open Access Journals (Sweden)

    Lucas Scheidt da Rosa

    2005-09-01

    Full Text Available Ateleia glazioviana Bail species is an arboreal of Fabaceae family, it is used for recovering degraded areas by showinga raised plasticity and rusticity growth. The objective of this work was to: (i evaluate the effect of polietilenoglicol 6000 on thegermination and (ii characterize the external and internal morphology of the seed and seedling. The study was carried out in TheForest Seeds Laboratory- Universidade Federal do Paraná (UFPR, in Parana State-Brazil. The experiment was established ingerbox (40 seeds on 6 filter papers with 20 mL of osmotic solution. Gerbox was sealed with PVC plastic film and led to germinate inMangelsdorf type chamber (under light at 25ºC . Six osmotic potential was tested: 0.0; -0.2; -0.4; -0.6; -0.8 and 1.0 MPa. It wasshowed that the germination is inversely proportional to the PEG concentration, no germination occurred at 1.0 MPa. External andinternal morphology of the seed and seedling was described and illustrated to the species. In conclusion, Ateleia glaziovianagermination is affected by osmotic potential, low level of percentage and speed germination occurred with increase of osmoticpotential. The germination was severely decreased at 0.4 Mpa.

  20. K8型单层球面网壳基于AUTODYN的外爆响应分析%RESPONSES OF SINGLE-LAYER RETICULATED DOMES SUBJECTED TO EXTERNAL BLAST LOADING USING AUTODYN

    Institute of Scientific and Technical Information of China (English)

    杨帆; 支旭东; 范峰

    2015-01-01

    The dynamic responses of single-layer reticulated domes are analyzed through the explicit dynamic finite element software AUTODYN.The load is applied using the FSI method,and the material is adopted using a multi-segment linear model for steel.First,the accuracy is verified by analyzing near-field and far-field explosions.Then the responses of a 20m span reticulated dome are obtained under external blast loading,including the loading spread,change in maximum nodal displacement,and development of plastic members.The laws governing structural response are researched,accounting for the mass of TNT,explosion distance,and explosion height.The results of numerical simulations indicate that AUTODYN can be used to analyze near-field and far-field explosions;the reticulated dome experiences two main shock wave loadings under external blast loading and the maximum nodal displacement occurs at the first shock wave loading;the plasticity development of structural members ends at 0.05 seconds;the structural responses strengthen with the increase of TNT mass and the explosion height,but weaken with the increase of explosion distance.%该文采用显式动力有限元软件AUTODYN对K8型单层球面网壳在外爆荷载下的动态响应进行了研究.数值模拟中采用流固耦合方法施加荷载,钢材采用多段线性模型,首先验证了AUTODYN进行近场爆炸分析和远场爆炸分析的准确性;考察了跨度为20 m的网壳结构在外爆荷载下的荷载传播规律、最大节点位移变化规律以及塑性杆件发展规律,考察了跨度为40 m网壳结构在TNT质量、炸点距离以及炸点高度参数变化下的结构响应规律.数值分析的结果表明:AUTODYN具备准确进行近场爆炸和远场爆炸分析的能力;单层球面网壳在外爆荷载下主要经历两次冲击波荷载,最大节点位移出现在第一次冲击荷载作用时,结构杆件的塑性发展在0.05 s后基本结束;网壳结构的响应随TNT质量增加和

  1. Capsules with external navigation and triggered release.

    Science.gov (United States)

    Shchukin, Dmitry G; Shchukina, Elena

    2014-10-01

    Encapsulation is an important technology for pharmaceutical industry, food production, et cetera. Its current level of development requires capsule functionalization. One of the interesting ideas to provide new functionality to the microcapsule and nanocapsule is layer-by-layer deposition of functional species. This technique provides step-by-step adsorption of various species (polyelectrolytes, nanoparticles, proteins) when the layer growth is controlled by electrostatic, hydrogen bonding, hydrophobic forces and forming multilayer shells with nanometer precision. This review article introduces recent achievements of layer-by-layer technique attaining external navigation ability and release properties the capsule shell.

  2. The External Degree.

    Science.gov (United States)

    Houle, Cyril O.

    This book examines the external degree in relation to the extremes of attitudes, myths, and data. Emphasis is placed on the emergence of the American external degree, foreign external-degree programs, the purpose of the external degree, the current scene, institutional issues, and problems of general policy. (MJM)

  3. 黑莓种子发芽试验%Experiment on the Seed Germination of Blackberry

    Institute of Scientific and Technical Information of China (English)

    李靖; 江国良; 孙淑霞; 陈栋; 谢红江

    2009-01-01

    [目的]为黑莓的栽培及育种筛选出较好的发芽方法.[方法]以黑莓栽培品种成熟鲜果中的饱满种子为材料,种子设3个不同处理:A、在胚根端剥离内果皮,保留种皮及胚乳层;B、在胚乳端剥离内果皮,保留种皮及胚乳层;C、不剥离.然后,用3种培养方法对黑莓种子进行发芽试验.[结果]在双层湿滤纸光培养中,处理A和B的种子发芽率均在40%左右,处理C的种子没有发芽;在双层湿滤纸暗培养中,处理A和B的种子发芽率均在61%以上,最高达63.6%,处理C的种子没有发芽.基质培养的种子的最高发芽率为15.1%.不同处理种子生成的小芽苗的移栽成活率均为100%.在培养基培养中,激素浓度配比对黑莓种子的发芽率没有影响.[结论]双层湿滤纸暗培养法是黑莓种子的理想发芽方法.%[Objective]The purpose was to screen out a better germination method for cultivating and breeding blackberry. [Method]With the full seeds from ripe and fresh fruits of blackberry cultivars as materials, they were treated by 3 different methods: A, the endocarp on radiculodium was peeled and the seed coat and endosperm layer were remained;B, the endocarp on endosperm end was peeled and the seed coat and endosperm layer were remained;C, non-peeled. Then, the germination enperiment was performed on the blackberry seeds by 3 culture methods. [Result]In the light culture with double-layer wet filter paper, the seed germination rates in both Treatment A and B were about 40% and there was no seed germinated in Treatment C. In the dark culture with double-layer wet filter paper, the seed germination rates in both Treatment A and B were higher than 61%, their highest germination rate was up to 63.6% and there was no seed germinated in Treatment C. The highest germination rate of seeds cultured on medium was 15.1%. The transplanting survival rates of germule seedlings grown from seeds treated by different methods were 100%. In the culture on

  4. Release of reactive oxygen intermediates (superoxide radicals, hydrogen peroxide, and hydroxyl radicals) and peroxidase in germinating radish seeds controlled by light, gibberellin, and abscisic acid.

    Science.gov (United States)

    Schopfer, P; Plachy, C; Frahry, G

    2001-04-01

    Germination of radish (Raphanus sativus cv Eterna) seeds can be inhibited by far-red light (high-irradiance reaction of phytochrome) or abscisic acid (ABA). Gibberellic acid (GA3) restores full germination under far-red light. This experimental system was used to investigate the release of reactive oxygen intermediates (ROI) by seed coats and embryos during germination, utilizing the apoplastic oxidation of 2',7'-dichlorofluorescin to fluorescent 2',7'-dichlorofluorescein as an in vivo assay. Germination in darkness is accompanied by a steep rise in ROI release originating from the seed coat (living aleurone layer) as well as the embryo. At the same time as the inhibition of germination, far-red light and ABA inhibit ROI release in both seed parts and GA3 reverses this inhibition when initiating germination under far-red light. During the later stage of germination the seed coat also releases peroxidase with a time course affected by far-red light, ABA, and GA3. The participation of superoxide radicals, hydrogen peroxide, and hydroxyl radicals in ROI metabolism was demonstrated with specific in vivo assays. ROI production by germinating seeds represents an active, developmentally controlled physiological function, presumably for protecting the emerging seedling against attack by pathogens.

  5. Influence of pretreatment and desiccation on the germination of Laurus nobilis L. seeds.

    Science.gov (United States)

    Tilki, Fahrettin

    2004-04-01

    The effects of moist stratification, gibberellic acid (GA3) in combination with cold-moist stratification and desiccation on the germination of bay laurel (Laurus nobilis L.) seeds were studied. It was found that the external fleshy pericarp caused dormancy. There was also embryo dormancy and it was broken in seeds lacking pericarp either warm-moist stratification (20 degrees C day/4 degrees C night) or cold-moist stratification (4 degrees C) for 8 and 10 weeks, respectively. Gibberellic acid had little effect on germination percent and germination value of seeds without pericarp when used alone but significantly increased overall germination performance when used with cold-moist stratification. The viability of seeds dropped when the moisture content of the seeds was reduced by desiccation, and the time required to reach the critical moisture levels in the seeds differed in the different desiccation temperatures. The critical minimum seed moisture content for bay laurel was around 15% and the seeds showed the typical behavior of recalcitrant seeds.

  6. Phospholipase Cδ regulates germination of Dictyostelium spores

    Directory of Open Access Journals (Sweden)

    Van Haastert Peter JM

    2001-12-01

    Full Text Available Abstract Background Many eukaryotes, including plants and fungi make spores that resist severe environmental stress. The micro-organism Dictyostelium contains a single phospholipase C gene (PLC; deletion of the gene has no effect on growth, cell movement and differentiation. In this report we show that PLC is essential to sense the environment of food-activated spores. Results Plc-null spores germinate at alkaline pH, reduced temperature or increased osmolarity, conditions at which the emerging amoebae can not grow. In contrast, food-activated wild-type spores return to dormancy till conditions in the environment allow growth. The analysis of inositol 1,4,5-trisphosphate (IP3 levels and the effect of added IP3 uncover an unexpected mechanism how PLC regulates spore germination: i deletion of PLC induces the enhanced activity of an IP5 phosphatase leading to high IP3 levels in plc-null cells; ii in wild-type spores unfavourable conditions inhibit PLC leading to a reduction of IP3 levels; addition of exogenous IP3 to wild-type spores induces germination at unfavourable conditions; iii in plc-null spores IP3 levels remain high, also at unfavourable environmental conditions. Conclusions The results imply that environmental conditions regulate PLC activity and that IP3 induces spore germination; the uncontrolled germination of plc-null spores is not due to a lack of PLC activity but to the constitutive activation of an alternative IP3-forming pathway.

  7. Combining Ability for Germination Traits in Jatropha curcas L.

    Directory of Open Access Journals (Sweden)

    A. K. M. Aminul Islam

    2013-01-01

    Full Text Available Six parents of Jatropha curcas were crossed in half diallel fashion, and the F1s were evaluated to determine the combining ability for nine germination parameters. The ratio between general combining ability (GCA and specific combining ability (SCA variances indicated preponderance of additive gene action for all the characters except germination percentage, time of 50% germination, seedling length, and seedling vigor index. The parents P1 and P2 were the best general combiner for most of the characters studied. The cross P1×P5 was the best specific combiner for speed of emergence, germination percentage, germination energy, germination index, and seedling vigor index, the cross P2×P5 for mean germination time, time of 50% germination, and seedling length, and the cross P4×P5 for number of days to first germination. The germination percentage varied from 58.06 to 92.76% among the parents and 53.43 to 98.96% among the hybrids. The highest germination (98.96% was observed in hybrid P2×P4, and none of the hybrids or parents showed 100% germination. The highest germination index (GI and seedling vigor index (SVI were found in hybrid P1×P5 and P2×P5, respectively. The results of this study provide clue for the improvement of Jatropha variety through breeding program.

  8. Combining ability for germination traits in Jatropha curcas L.

    Science.gov (United States)

    Islam, A K M Aminul; Anuar, Nurina; Yaakob, Zahira; Ghani, Jaharah A; Osman, Mohamad

    2013-01-01

    Six parents of Jatropha curcas were crossed in half diallel fashion, and the F 1s were evaluated to determine the combining ability for nine germination parameters. The ratio between general combining ability (GCA) and specific combining ability (SCA) variances indicated preponderance of additive gene action for all the characters except germination percentage, time of 50% germination, seedling length, and seedling vigor index. The parents P 1 and P 2 were the best general combiner for most of the characters studied. The cross P 1 × P 5 was the best specific combiner for speed of emergence, germination percentage, germination energy, germination index, and seedling vigor index, the cross P 2 × P 5 for mean germination time, time of 50% germination, and seedling length, and the cross P 4 × P 5 for number of days to first germination. The germination percentage varied from 58.06 to 92.76% among the parents and 53.43 to 98.96% among the hybrids. The highest germination (98.96%) was observed in hybrid P 2 × P 4, and none of the hybrids or parents showed 100% germination. The highest germination index (GI) and seedling vigor index (SVI) were found in hybrid P 1 × P 5 and P 2 × P 5, respectively. The results of this study provide clue for the improvement of Jatropha variety through breeding program.

  9. Localization of phytase transcripts in germinating seeds of the common bean (Phaseolus vulgaris L.).

    Science.gov (United States)

    Lazali, Mohamed; Louadj, Lamia; Ounane, Ghania; Abadie, Josiane; Amenc, Laurie; Bargaz, Adnane; Lullien-Pellerin, Valérie; Drevon, Jean-Jacques

    2014-09-01

    The work provides the first-time evidence of tissue-specific expression of a phytase gene in the germinating seeds of Phaseolus vulgaris. Phytase enzyme plays a major role in germinating seeds. It is also active during N2 fixation within nodules of legumes. The effect of phosphorus (P) deficiency on phytase gene expression and localization in N2-fixing root nodules has been recently studied in hydroaeroponic culture of Phaseolus vulgaris. In this study, phytase gene transcripts within the germinating seed tissues of the P-inefficient P. vulgaris recombinant inbred line RIL147 were in situ localized with a similar RT-PCR recipe as that used for nodules. Our results show that the phytase gene expression was mainly localized in the outer layers, vascular cells and parenchyma of germinating seeds whereas it was localized in the inner and middle cortex of nodules. Image analysis quantified higher fluorescence intensity of the phytase transcript signal in the seed embryo than in radicles, cotyledons or the nodule cortex. Furthermore, the phytase activity was 22-fold higher in cotyledons (43 nmol min(-1) g(-1) dry weight) than in nodules (2 nmol min(-1) g(-1) dry weight). The K m and V m values of phytase activity in cotyledons were also significantly higher than in nodules. Interestingly, the amplified sequence of cDNA phytase exhibited highest homology with the Glycine max purple acid phosphatase (NM_001289274) 90 % for germinating seed as compared to nodule phytase cDNA displaying 94 % homology with the Glycine max phytase (GQ422774.1). It is concluded that phytase enzymes are likely to vary from seeds to nodules and that phytase enzymes play key roles in the use of organic P or N2 fixation, as it is well known for germination.

  10. [The theory of germ layers: the debatable aspects].

    Science.gov (United States)

    Dondua, A K

    1994-01-01

    Data on early embryonic development of animals provided the basis for the following conclusions. In most (if not in all) species, germinal layers are not primitive structures recapitulating the initial organs of ancestral forms. The initial cell differentiation in the embryo is not directly associated with gastrulation, and the common concept of a fundamental relationship between germinal layer formation and cell differentiation is erroneous. Specification of cell types during early development and morphogenetic movements during gastrulation are relatively autonomous processes controlled by different genetic systems. The formation of germinal layers during individual development of different multicellular animals can be understood taking into account that segregation of cell layers is an essential element of epithelial morphogenesis. Movement of cells and cell layers during gastrulation is a specific manifestation of a general morphogenetic principle.

  11. Regulating multiple externalities

    DEFF Research Database (Denmark)

    Waldo, Staffan; Jensen, Frank; Nielsen, Max

    2016-01-01

    Open access is a well-known externality problem in fisheries causing excess capacity and overfishing. Due to global warming, externality problems from CO2 emissions have gained increased interest. With two externality problems, a first-best optimum can be achieved by using two regulatory instrume......Open access is a well-known externality problem in fisheries causing excess capacity and overfishing. Due to global warming, externality problems from CO2 emissions have gained increased interest. With two externality problems, a first-best optimum can be achieved by using two regulatory...

  12. Germination of Croton urucurana L. seeds exposed to different storage temperatures and pre-germinative treatments.

    Science.gov (United States)

    Scalon, Silvana P Q; Mussury, Rosilda M; Lima, Andréa A

    2012-03-01

    The present work evaluated the germinability and vigor of Croton urucurana seeds. 1) Seeds were sorted by color (caramel, gray and black) and were subjected to seven different pre-germination treatments followed by incubation at 20ºC, 25°C or 20/30°C. 2) Seeds were stored in cold chambers or at room temperature for up to 300 days and were subsequently incubated at 20/30ºC in a germination chamber or under greenhouse conditions. Only gray seeds showed significant germination rates. The highest first count percentages of total germination and the highest germination speed indices were observed in control seeds and in those which were treated with water or 200 mg.L(-1) gibberellic acid for 12 hours. Seeds stored under refrigeration showed the highest values for all of the characteristics examined, as well as less electrical conductivity of the imbibing solution. Seedlings were more vigorous when seeds were stored for 300 days in a cold chamber. The seedlings production can be increased by incubating the seeds at alternating temperatures (20/30°C). The seeds do not need pre-germination treatments.

  13. ExternE National Implementation Finland

    Energy Technology Data Exchange (ETDEWEB)

    Pingoud, K.; Maelkki, H.; Wihersaari, M.; Pirilae, P. [VTT Energy, Espoo (Finland); Hongisto, M. [Imatran Voima Oy, Vantaa (Finland); Siitonen, S. [Ekono Energy Ltd, Espoo (Finland); Johansson, M. [Finnish Environment Institute, Helsinki (Finland)

    1999-07-01

    ExternE National Implementation is a continuation of the ExternE Project, funded in part by the European Commission's Joule III Programme. This study is the result of the ExternE National Implementation Project for Finland. Three fuel cycles were selected for the Finnish study: coal, peat and wood-derived biomass, which together are responsible for about 40% of total electricity generation in Finland and about 75% of the non-nuclear fuel based generation. The estimated external costs or damages were dominated by the global warming (GW) impacts in the coal and peat fuel cycles, but knowledge of the true GW impacts is still uncertain. From among other impacts that were valued in monetary terms the human health damages due to airborne emissions dominated in all the three fuel cycles. Monetary valuation for ecosystem impacts is not possible using the ExternE methodology at present. The Meri-Pori power station representing the coal fuel cycle is one of the world's cleanest and most efficient coal-fired power plants with a condensing turbine. The coal is imported mainly from Poland. The estimated health damages were about 4 mECU/kWh, crop damages an order of magnitude lower and damages caused to building materials two orders of magnitude lower. The power stations of the peat and biomass fuel cycles are of CHP type, generating electricity and heat for the district heating systems of two cities. Their fuels are of domestic origin. The estimated health damages allocated to electricity generation were about 5 and 6 mECU/kWh, respectively. The estimates were case-specific and thus an generalisation of the results to the whole electricity generation in Finland is unrealistic. Despite the uncertainties and limitations of the methodology, it is a promising tool in the comparison of similar kinds of fuel cycles, new power plants and pollution abatement technologies and different plant locations with each other. (orig.)

  14. Effect of chromium toxicity on germination and early seedling growth ...

    African Journals Online (AJOL)

    USER

    2010-07-19

    Jul 19, 2010 ... causing toxicity to plants as exhibited by reduced seed germination ... hypochlorite for 1 min to prevent fungal attack, and triple-rinsed in distilled ..... Effects of arsenic on seed germination and physiological activities of wheat.

  15. Thermogenetic curves and thermokinetics of seed germination of Robinia pseudoacaia

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Seed germination process has closely relation with material transformation and energy exchange within the seed. Study on its thermal effect is important for understanding the mechanism and the influencing factors of the seed germination. The thermogenetic curves of seed germination of Robinia pseudoacacia was measured by a new-type conductive microcalo-rimeter made in Wuhan University. The relationship was analyzed between the germination thermogenetic regulation and seed germination physiology. The thermogentic curves were further analyzed by thermokinetic theory to obtain the dynamic parameters and the thermokinetic model on seed germination of Robinia pseudoacacia. The relationship of the thermogenetic power(μw) and the germination time(h) of the germination process of 20 grains Robinia pseudocacia seeds at 25℃ was P=208.77/[0.1937+0.8063exp(-0.06563t)

  16. Wet Permeability Characteristics of Double-layer Knitted Fabrics

    Institute of Scientific and Technical Information of China (English)

    WANG Qi; XI Bai-jun

    2007-01-01

    In order to solve the problem that sweat flows back into the internal layer from the external layer in doublelayer knits, a fabric structure model is set up and the conditions that keep the sweat from flowing back into the internal layer from the external layer are presented. It can be used to improve the design of the double-layer knitstheoretically.

  17. Measuring Total and Germinable Spore Populations

    Science.gov (United States)

    Noell, A.C.; Yung, P.T.; Yang, W.; Lee, C.; Ponce, A.

    2011-01-01

    It has been shown that bacterial endospores can be enumerated using a microscopy based assay that images the luminescent halos from terbium ions bound to dipicolinic acid, a spore specific chemical marker released upon spore germination. Further development of the instrument has simplified it towards automation while at the same time improving image quality. Enumeration of total spore populations has also been developed allowing measurement of the percentage of viable spores in any population by comparing the germinable/culturable spores to the total. Percentage viability will allow a more quantitative comparison of the ability of spores to survive across a wide range of extreme environments.

  18. Biochemical Changes During Seed Germination of Sterculia urens Roxb.

    OpenAIRE

    Botcha SATYANARAYANA; Prattipati Subhashini DEVI; Atluru ARUNDATHI

    2011-01-01

    The present study describes biochemical changes taking place during seed germination of Sterculia urens. The levels of proteins, total amino acids, reducing sugars, total soluble sugars and lipids were studied during various stages of seed germination (0-15 days). Total protein content was decreased in cotyledons during seed germination while free amino acid content increased to its maximum extent by 9th day of germination and reverse trend thereafter. The levels of reducing sugars and total ...

  19. Factors Defining Field Germination of Oilseed Radish Seeds

    Directory of Open Access Journals (Sweden)

    N.V. Dorofeev

    2013-08-01

    Full Text Available Influence of temperature, depth of crops and granulometric of soil structure on germination speed, laboratory and field germination of oilseed radish seeds were studied. It was established that the period of seed-germination is defined both by temperature and granulometric structure of soil. The highest field germination was marked on sandy loam at depth of crops' seeds at 3 cm and 20°С.

  20. Factors Defining Field Germination of Oilseed Radish Seeds

    OpenAIRE

    N.V. Dorofeev; E.V. Bojarkin; A.A. Peshkova

    2013-01-01

    Influence of temperature, depth of crops and granulometric of soil structure on germination speed, laboratory and field germination of oilseed radish seeds were studied. It was established that the period of seed-germination is defined both by temperature and granulometric structure of soil. The highest field germination was marked on sandy loam at depth of crops' seeds at 3 cm and 20°С.

  1. The pleiotropic effects of the seed germination inhibitor germostatin

    OpenAIRE

    Ye, Yajin; Zhao, Yang

    2016-01-01

    Seed dormancy and germination are the most important adaptive traits of seed plants, which control the germination in a proper space and time. Internal genetic factors together with environmental cues govern seed dormancy and germination. Abscisic acid (ABA), a key phytohormone induces seed dormancy and inhibits seed germination through its molecular genetic signaling network responding the seed inherent physiological and environmental factors. Recently, auxin has been shown to be another phy...

  2. ASH External Web Portal (External Portal) -

    Data.gov (United States)

    Department of Transportation — The ASH External Web Portal is a web-based portal that provides single sign-on functionality, making the web portal a single location from which to be authenticated...

  3. Starch bioengineering affects cereal grain germination and seedling establishment

    DEFF Research Database (Denmark)

    Shaik, Shahnoor Sultana; Carciofi, Massimiliano; Martens, Helle Juel

    2014-01-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule...

  4. DOG1-imposed dormancy mediates germination responses to temperature cues

    NARCIS (Netherlands)

    Murphey, M.; Kovach, K.; Elnacash, T.; He, H.; Bentsink, L.; Donohue, K.

    2015-01-01

    Seed dormancy and environment-dependent germination requirements interact to determine the timing of germination in natural environments. This study tested the contribution of the dormancy gene Delay Of Germination 1 (DOG1) to primary and secondary dormancy induction in response to environmental

  5. Factors affecting the germination of hybrid rose achenes

    NARCIS (Netherlands)

    Vries, De D.P.; Dubois, L.A.M.

    2015-01-01

    The smooth germination of mature Hybrid rose achenes is hampered by (i) hardseededness (HS), (ii) primary dormancy (PD) and (iii) germination polymorphism (GP). HS is owing to the hard pericarp. PD is, in principle, a natural phenomenon that protects the seeds from precocious germination. For ger

  6. Effect of Natural Brassinolide on Germination of Ailanthus altissima Seeds

    Institute of Scientific and Technical Information of China (English)

    Li Kai-rong; Zhang Wei-bing; Li Hui-ke

    2005-01-01

    The germination capacity of Ailanthus altissima seeds improved after the seeds were soaked with different concentrations of natural brassinolide (NBR). The germination rate and germination energy of the seeds increased by 17.6% and 18.8%, and treatment, compared with the control. After hypocotyls ofA. altissima were treated with NBR, the elongation of the hypocotyls inA. altissima hypocotyls.

  7. Factors affecting the germination of hybrid rose achenes

    NARCIS (Netherlands)

    Vries, De D.P.; Dubois, L.A.M.

    2015-01-01

    The smooth germination of mature Hybrid rose achenes is hampered by (i) hardseededness (HS), (ii) primary dormancy (PD) and (iii) germination polymorphism (GP). HS is owing to the hard pericarp. PD is, in principle, a natural phenomenon that protects the seeds from precocious germination. For ger

  8. Tomato Seed Coat Permeability to Selected Carbon Nanomaterials and Enhancement of Germination and Seedling Growth.

    Science.gov (United States)

    Ratnikova, Tatsiana A; Podila, Ramakrishna; Rao, Apparao M; Taylor, Alan G

    2015-01-01

    Seed coat permeability was examined using a model that tested the effects of soaking tomato (Solanum lycopersicon) seeds in combination with carbon-based nanomaterials (CBNMs) and ultrasonic irradiation (US). Penetration of seed coats to the embryo by CBNMs, as well as CBNMs effects on seed germination and seedling growth, was examined. Two CBNMs, C60(OH)20 (fullerol) and multiwalled nanotubes (MWNTs), were applied at 50 mg/L, and treatment exposure ranged from 0 to 60 minutes. Bright field, fluorescence, and electron microscopy and micro-Raman spectroscopy provided corroborating evidence that neither CBNM was able to penetrate the seed coat. The restriction of nanomaterial (NM) uptake was attributed to the semipermeable layer located at the innermost layer of the seed coat adjacent to the endosperm. Seed treatments using US at 30 or 60 minutes in the presence of MWNTs physically disrupted the seed coat; however, the integrity of the semipermeable layer was not impaired. The germination percentage and seedling length and weight were enhanced in the presence of MWNTs but were not altered by C60(OH)20. The combined exposure of seeds to NMs and US provided insight into the nanoparticle-seed interaction and may serve as a delivery system for enhancing seed germination and early seedling growth.

  9. Control of Seed Germination and Plant Development by Carbon and Nitrogen Availability

    Science.gov (United States)

    Osuna, Daniel; Prieto, Pilar; Aguilar, Miguel

    2015-01-01

    Little is known about the molecular basis of the influence of external carbon/nitrogen (C/N) ratio and other abiotic factors on phytohormones regulation during seed germination and plant developmental processes, and the identification of elements that participate in this response is essential to understand plant nutrient perception and signaling. Sugars (sucrose, glucose) and nitrate not only act as nutrients but also as signaling molecules in plant development. A connection between changes in auxin transport and nitrate signal transduction has been reported in Arabidopsis thaliana through the NRT1.1, a nitrate sensor and transporter that also functions as a repressor of lateral root growth under low concentrations of nitrate by promoting auxin transport. Nitrate inhibits the elongation of lateral roots, but this effect is significantly reduced in abscisic acid (ABA)-insensitive mutants, what suggests that ABA might mediate the inhibition of lateral root elongation by nitrate. Gibberellin (GA) biosynthesis has been also related to nitrate level in seed germination and its requirement is determined by embryonic ABA. These mechanisms connect nutrients and hormones signaling during seed germination and plant development. Thus, the genetic identification of the molecular components involved in nutrients-dependent pathways would help to elucidate the potential crosstalk between nutrients, nitric oxide (NO) and phytohormones (ABA, auxins and GAs) in seed germination and plant development. In this review we focus on changes in C and N levels and how they control seed germination and plant developmental processes through the interaction with other plant growth regulators, such as phytohormones. PMID:26635847

  10. Novel hydrated graphene ribbon unexpectedly promotes aged seed germination and root differentiation.

    Science.gov (United States)

    Hu, Xiangang; Zhou, Qixing

    2014-01-21

    It is well known that graphene (G) induces nanotoxicity towards living organisms. Here, a novel and biocompatible hydrated graphene ribbon (HGR) unexpectedly promoted aged (two years) seed germination. HGR formed at the normal temperature and pressure (120 days hydration), presented 17.1% oxygen, 0.9% nitrogen groups, disorder-layer structure, with 0.38 nm thickness ribbon morphology. Interestingly, there were bulges around the edges of HGR. Compared to G and graphene oxide (GO), HGR increased seed germination by 15% root differentiation between 52 and 59% and enhanced resistance to oxidative stress. The metabonomics analysis discovered that HGR upregulated carbohydrate, amino acid, and fatty acids metabolism that determined secondary metabolism, nitrogen sequestration, cell membrane integrity, permeability, and oxidation resistance. Hexadecanoic acid as a biomarker promoted root differentiation and increased the germination rate. Our discovery is a novel HGR that promotes aged seed germination, illustrates metabolic specificity among graphene-based materials, and inspires innovative concepts in the regulation of seed development.

  11. Proteomics of Arabidopsis seed germination and priming

    NARCIS (Netherlands)

    Gallardo, K.; Job, C.; Groot, S.P.C.; Puype, M.; Demol, H.; Vandekerckhove, J.; Job, D.

    2003-01-01

    To better understand seed germination, a complex developmental process, we developed a proteome analysis of the model plant Arabidopsis for which complete genome sequence is now available. Among about 1,300 total seed proteins resolved in two-dimensional gels, changes in the abundance (up- and down-

  12. Seed dormancy and germination: light and nitrate.

    NARCIS (Netherlands)

    Hilhorst, H.W.M.

    1990-01-01

    One of the most important aspects of the life cycle of seed plants is the formation and development of seeds on the motherplant and the subsequent dispersal. An equally important element of the survival strategy is the ability of seeds to prevent germination in unfavorable conditions, such as th

  13. Unravelling desiccation tolerance in germinated Arabidopsis seeds

    NARCIS (Netherlands)

    Maia de Oliveira, J.

    2014-01-01

    How different organisms survive in the absence or under very limited amounts of water is still an open question. The aim of the research presented in this thesis is to explore the molecular basis of desiccation tolerance in seeds. We investigated the possibilities of using germinated desiccation sen

  14. Seed priming with antioxidants improves sunflower seed germination and seedling growth under unfavorable germination conditions

    OpenAIRE

    DRAGANIC, Ivana; LEKIC, Slavoljub

    2014-01-01

    The results of studying the effects of sunflower seed priming with an aqueous solution of ascorbic acid (A), tocopherol (T), and glutathione (G) performed prior to accelerated ageing and a cold test are presented in this paper. Germination, the percentage of abnormal seedlings, and the lengths of both roots and shoots were monitored. The results showed that the cold test caused a drastic drop in germination, an adverse effect on the shoot length, an increase in the percentage of abnormal seed...

  15. Investigation on carob seed germination under controlled conditions

    Directory of Open Access Journals (Sweden)

    Hamide GÜBBÜK

    2012-12-01

    Full Text Available In this study, the effects of some pre-treatments on seed germination of wild carob seeds were investigated under two different conditions (germination cabinet and greenhouse. Twenty two pre-treatments were applied to the seeds. Pre-treated and control seeds were placed under dark conditions at 25°C. All treated seeds were germinated at 27°C temperature in the germination cabinet and greenhouse conditions. Seed germination rate was determined according to the pre-treatments for both conditions. The results showed that if the seeds were soaked in pure (98 % or diluted sulphuric acid (H2SO4, 40 %, 90 % for 30 minutes then kept in water for 2 days or just soaking the seeds in H2SO4 sulfuric acid for 30 minute gave the best results in terms of seed germination as the seed germination rate was over 90 %. The lowest germination rate under both conditions was observed in the control and soaking the seeds in 60 % H2SO4 for 30 minutes. On the other hands, seeds soaked in 60 % H2SO4 and then kept in water for 2 days did not germinate as they lost germination ability. The highest germination rates were recorded after ten days of pre-treatments in both conditions.

  16. Germination and Dormancy in Annual Halophyte Juncus ranarius Song & Perr.

    Directory of Open Access Journals (Sweden)

    Jeremi KOŁODZIEJEK

    2015-12-01

    Full Text Available The effects of cold stratification and gibberellic acid (GA3 on dormancy breaking for seeds of the annual halophyte species Juncus ranarius were tested. Germination percentage and recovery responses of salt stressed seeds were also tested. Freshly collected seeds germinated slowly under all incubation conditions. Thus, the seeds of J. ranarius have physiological dormancy, e.g. they are water permeable, have a fully developed embryo and require cold stratification to come out of dormancy. Furthermore, promotion of germination by GA3 after-ripening in dry storage also indicated that these seeds have non-deep physiological dormancy. In general, the higher the GA3 concentration, the more germination occurred within the studied range. Juncus ranarius demonstrated a germination preference for light. The highest germination percentage and rate of germination were recorded under constant light conditions at 22 °C after 24 weeks of cold stratification. In saline solutions, the highest percentage of germination was obtained at 25 mM L-1 NaCl, and further increase in salinity resulted in a gradual decrease in germination. However, ungerminated seeds were not damaged by salt, showing a high level of recovery. The greater the reduction in salinity, the better the germination rate became. It was concluded that dormancy could be completely broken by cold stratification, indicating spring germination. Juncus ranarius can grow well at lower NaCl concentrations under constant light conditions at 22 °C.

  17. Bryophyte spore germinability is inhibited by peatland substrates

    Science.gov (United States)

    Bu, Zhao-Jun; Li, Zhi; Liu, Li-Jie; Sundberg, Sebastian; Feng, Ya-Min; Yang, Yun-He; Liu, Shuang; Song, Xue; Zhang, Xing-Lin

    2017-01-01

    Bryophyte substrates and species may affect spore germination through allelopathy. Polytrichum strictum is currently expanding in peatlands in north-eastern China - is this an effect of its superior spore germinability or do its gametophytes have a stronger allelopathic effect than do Sphagnum? We conducted a spore burial experiment to test the effect of species identity, substrate and water table depth (WTD) on spore germinability and bryophyte allelopathic effect with P. strictum and two Sphagnum species (S. palustre and S. magellanicum). After 5 months of burial during a growing season, the spores were tested for germinability. Allelopathic effect of bryophyte substrates was assessed by the difference between spore germinability after being stored inside or outside the substrates. After burial, more than 90% of the spores lost their germinability across all three species due to ageing and allelopathy. Spore germinability differed among species, where the spores in S. palustre had a higher germination frequency than those in P. strictum. The three bryophytes maintained a higher germinability in Sphagnum than in Polytrichum hummocks, probably due to a stronger allelopathic effect of P. strictum. Water table drawdown by 10 cm increased germinability by more than 60% across the three species. The study indicates that P. strictum does not possess an advantage regarding spore germination but rather its gametophytes have a stronger allelopathic effect. Due to the weaker inhibitive effect of Sphagnum gametophytes, P. strictum may have a potential establishment superiority over Sphagnum in peatlands, in addition to a better drought tolerance, which may explain its current expansion.

  18. Biochemical Changes During Seed Germination of Sterculia urens Roxb.

    Directory of Open Access Journals (Sweden)

    Botcha SATYANARAYANA

    2011-08-01

    Full Text Available The present study describes biochemical changes taking place during seed germination of Sterculia urens. The levels of proteins, total amino acids, reducing sugars, total soluble sugars and lipids were studied during various stages of seed germination (0-15 days. Total protein content was decreased in cotyledons during seed germination while free amino acid content increased to its maximum extent by 9th day of germination and reverse trend thereafter. The levels of reducing sugars and total soluble sugars increased till 6th day of germination and decreased thereafter. The lipid content was high at initial stages of germination (0-6 days but gradually decreased by 15th day of germination.

  19. A model for quantification of temperature profiles via germination times

    DEFF Research Database (Denmark)

    Pipper, Christian Bressen; Adolf, Verena Isabelle; Jacobsen, Sven-Erik

    2013-01-01

    Current methodology to quantify temperature characteristics in germination of seeds is predominantly based on analysis of the time to reach a given germination fraction, that is, the quantiles in the distribution of the germination time of a seed. In practice interpolation between observed...... time and a specific type of accelerated failure time models is provided. As a consequence the observed number of germinated seeds at given monitoring times may be analysed directly by a grouped time-to-event model from which characteristics of the temperature profile may be identified and estimated...... germination fractions at given monitoring times is used to obtain the time to reach a given germination fraction. As a consequence the obtained value will be highly dependent on the actual monitoring scheme used in the experiment. In this paper a link between currently used quantile models for the germination...

  20. External radiation surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, E.J.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report describes how external radiation was measured, how surveys were performed, and the results of these measurements and surveys. External radiation exposure rates were measured at locations on and off the Hanford Site using thermoluminescent dosimeters (TLD). External radiation and contamination surveys were also performed with portable radiation survey instruments at locations on and around the Hanford Site.

  1. Embryo development and corresponding factors affecting in vitro germination of Cymbidium faberi × C. sinense hybrid seeds

    Directory of Open Access Journals (Sweden)

    Li Fengtong

    2016-01-01

    Full Text Available A better understanding of embryo development would provide insights into seed quality and subsequent germination events in the interspecific hybridization of Cymbidium faberi ‘Jiepeimei’ × C. sinense ‘Qijianheimo’. At the mature stage, 26.1% of the ovules were abnormal. Most of the hybrid embryos could develop normally. Abortions mainly occurred at the zygote (9.5% and 2-4-celled embryo (15.1% stages. No germination was observed at 90 and 105 days after pollination (DAP, when the embryo was at the early globular stage, with abundant organelles but no storage materials. During 110-130 DAP, the globular embryo was formed and the starch grains began to accumulate in plastids. The hybrid seeds collected at 120 DAP showed initiation of germination. Germination significantly increased at 135 DAP and was maximal at 150 DAP, during which period the hybrid embryos developed into the late globular stage. The storage materials, i.e. lipid and protein bodies, began to accumulate and the filamentary structures derived from suspensor cells still persisted. After the seeds matured (160 DAP, the germination percentage declined sharply. Safranin staining revealed that the outer seed coat was totally cuticularized and the inner seed coat appeared as a cuticle layer enclosing the embryo proper tightly, which may be the main factor inhibiting the subsequent germination of hybrid seeds. In conclusion, 150 DAP should be the opportune time for the in vitro germination of C. faberi ‘Jiepeimei’ × C. sinense ‘Qijianheimo’ hybrid seeds.

  2. Mechanisms of Induction of Germination of Bacillus subtilis Spores by High Pressure

    OpenAIRE

    Paidhungat, Madan; Setlow, Barbara; Daniels, William B.; Hoover, Dallas; Papafragkou, Efstathia; Setlow, Peter

    2002-01-01

    Spores of Bacillus subtilis lacking all germinant receptors germinate >500-fold slower than wild-type spores in nutrients and were not induced to germinate by a pressure of 100 MPa. However, a pressure of 550 MPa induced germination of spores lacking all germinant receptors as well as of receptorless spores lacking either of the two lytic enzymes essential for cortex hydrolysis during germination. Complete germination of spores either lacking both cortex-lytic enzymes or with a cortex not att...

  3. In vitro germination of desert rose varieties(

    Directory of Open Access Journals (Sweden)

    Tatiane Lemos Varella

    2015-08-01

    Full Text Available The drought stress resistance is a characteristic of the desert rose and its estimable beauty flowers, which gave it great relevance in the ornamental market. However, the desert rose production and germination is hampered by possible sterility of their male and female flowers and frequent problems in pollination, so the tissue culture is a promising alternative to the propagation of these plants. This study aimed to evaluate the effect of gibberellic acid on four commercial varieties of desert rose (Adenium obesum cultivated in vitro. The seeds of the varieties ‘Orange Pallet’, ‘Carnation violet’, ‘Diamond ring’ and ‘Vermiliont’ were sterilized and inoculated on Water + Agar (T0, medium MS (T1, ½ MS (T2, MS + 0.25 mg L-1 GA3 (T3, MS + 0.5 mg L-1 GA3 (T4, ½ MS + 0.25 mg L-1 GA3 (T5, ½ MS 0.5 mg L-1 GA3 (T6. The seeds germination of A. obesum was initiated on the fourth day of cultivation and on the tenth day was possible to observe the expansion of the cotyledons and leaf expansion with subsequent development of early secondary root. The ‘Orange pallet’ variety germinated 100% of seeds on water + agar and MS ½ + 0.5 mg L-1 of GA3. For ‘Diamond Ring’ and ‘Carnation violet’ the highest rate of germination occurred in treatments MS ½; 0.25 mg L-1 GA3; MS + 0.5 mg L-1 GA3 MS ½ + 0.5 mg L-1 GA3 averaging 80% and 70%, respectively. For ‘Vermiliont’ the best response was in MS and MS ½ + 0.5 mg L-1 GA3 ranging between 70-90% germinated embryos. It was registered different malformations in all treatments like absence of roots and apexes during seedling development. The concentrations of GA3 did not affect significantly the seed germination.

  4. EFFECTS OF PRE-GERMINATION TREATMENTS AND STORAGE ON GERMINATION OF Astronium fraxinifolium SCHOTT (ANACARDIACEAE DIASPORES

    Directory of Open Access Journals (Sweden)

    Lílian de Lima Braga

    2014-01-01

    Full Text Available The goal of this study was to evaluate the germination and the storage capacity of Astronium fraxinifolium diaspores. Six pre-germination treatments were used in the experiment: control treatment (intact diaspores; diaspores immersed in water at room temperature (25º C for 5 min; diaspores immersed in water at 70° C for 5 min; diaspores immersed in water at 100° C for 5 min; diaspores immersed in sodium hypochlorite solution (1:1000 for 2 min; and diaspores mechanically scarified with sandpaper #80. To evaluate storage conditions, we tested two different types of packaging (permeable paper bag and transparent glass jar and two environmental conditions (cold chamber and room conditions, resulting in four treatments. The germination tests were performed for zero (control and 60, 120, 180, 240, 300 and 360 days after storage. The effects of different treatments on germination and storage of diaspores were evaluated by ANOVA, followed by Tukey test. Regarding to pre-germination treatments, high germination rates were observed in the hypochlorite (98.0 ± 4.22%, control (97.0 ± 4.83%, water at room temperature (96.0 ± 6.99% and water at 70º C (83.0 ± 29.08% treatments. Thus, Astronium fraxinifolium diaspores do not present dormancy. During storage, the diaspores remained viable throughout the study period with high germination rates, except for the treatment in paper bags placed in the cold chamber, in which the diaspores lost their viability in the eighth month of storage. Therefore, this is not a recommended storage method for this species.

  5. EFFECTS OF PRE-GERMINATION TREATMENTS AND STORAGE ON GERMINATION OF Astronium fraxinifolium SCHOTT (ANACARDIACEAE DIASPORES

    Directory of Open Access Journals (Sweden)

    Lílian de Lima Braga

    2014-06-01

    Full Text Available http://dx.doi.org/10.5902/1980509814577The goal of this study was to evaluate the germination and the storage capacity of Astronium fraxinifolium diaspores. Six pre-germination treatments were used in the experiment: control treatment (intact diaspores; diaspores immersed in water at room temperature (25º C for 5 min; diaspores immersed in water at 70° C for 5 min; diaspores immersed in water at 100° C for 5 min; diaspores immersed in sodium hypochlorite solution (1:1000 for 2 min; and diaspores mechanically scarified with sandpaper #80. To evaluate storage conditions, we tested two different types of packaging (permeable paper bag and transparent glass jar and two environmental conditions (cold chamber and room conditions, resulting in four treatments. The germination tests were performed for zero (control and 60, 120, 180, 240, 300 and 360 days after storage. The effects of different treatments on germination and storage of diaspores were evaluated by ANOVA, followed by Tukey test. Regarding to pre-germination treatments, high germination rates were observed in the hypochlorite (98.0 ± 4.22%, control (97.0 ± 4.83%, water at room temperature (96.0 ± 6.99% and water at 70º C (83.0 ± 29.08% treatments. Thus, Astronium fraxinifolium diaspores do not present dormancy. During storage, the diaspores remained viable throughout the study period with high germination rates, except for the treatment in paper bags placed in the cold chamber, in which the diaspores lost their viability in the eighth month of storage. Therefore, this is not a recommended storage method for this species.

  6. Role of YpeB in Cortex Hydrolysis during Germination of Bacillus anthracis Spores

    Science.gov (United States)

    Bernhards, Casey B.

    2014-01-01

    The infectious agent of the disease anthrax is the spore of Bacillus anthracis. Bacterial spores are extremely resistant to environmental stresses, which greatly hinders spore decontamination efforts. The spore cortex, a thick layer of modified peptidoglycan, contributes to spore dormancy and resistance by maintaining the low water content of the spore core. The cortex is degraded by germination-specific lytic enzymes (GSLEs) during spore germination, rendering the cells vulnerable to common disinfection techniques. This study investigates the relationship between SleB, a GSLE in B. anthracis, and YpeB, a protein necessary for SleB stability and function. The results indicate that ΔsleB and ΔypeB spores exhibit similar germination phenotypes and that the two proteins have a strict codependency for their incorporation into the dormant spore. In the absence of its partner protein, SleB or YpeB is proteolytically degraded soon after expression during sporulation, rather than escaping the developing spore. The three PepSY domains of YpeB were examined for their roles in the interaction with SleB. YpeB truncation mutants illustrate the necessity of a region beyond the first PepSY domain for SleB stability. Furthermore, site-directed mutagenesis of highly conserved residues within the PepSY domains resulted in germination defects corresponding to reduced levels of both SleB and YpeB in the mutant spores. These results identify residues involved in the stability of both proteins and reiterate their codependent relationship. It is hoped that the study of GSLEs and interacting proteins will lead to the use of GSLEs as targets for efficient activation of spore germination and facilitation of spore cleanup. PMID:25022853

  7. Role of YpeB in cortex hydrolysis during germination of Bacillus anthracis spores.

    Science.gov (United States)

    Bernhards, Casey B; Popham, David L

    2014-10-01

    The infectious agent of the disease anthrax is the spore of Bacillus anthracis. Bacterial spores are extremely resistant to environmental stresses, which greatly hinders spore decontamination efforts. The spore cortex, a thick layer of modified peptidoglycan, contributes to spore dormancy and resistance by maintaining the low water content of the spore core. The cortex is degraded by germination-specific lytic enzymes (GSLEs) during spore germination, rendering the cells vulnerable to common disinfection techniques. This study investigates the relationship between SleB, a GSLE in B. anthracis, and YpeB, a protein necessary for SleB stability and function. The results indicate that ΔsleB and ΔypeB spores exhibit similar germination phenotypes and that the two proteins have a strict codependency for their incorporation into the dormant spore. In the absence of its partner protein, SleB or YpeB is proteolytically degraded soon after expression during sporulation, rather than escaping the developing spore. The three PepSY domains of YpeB were examined for their roles in the interaction with SleB. YpeB truncation mutants illustrate the necessity of a region beyond the first PepSY domain for SleB stability. Furthermore, site-directed mutagenesis of highly conserved residues within the PepSY domains resulted in germination defects corresponding to reduced levels of both SleB and YpeB in the mutant spores. These results identify residues involved in the stability of both proteins and reiterate their codependent relationship. It is hoped that the study of GSLEs and interacting proteins will lead to the use of GSLEs as targets for efficient activation of spore germination and facilitation of spore cleanup.

  8. Identification of a Novel Lipoprotein Regulator of Clostridium difficile Spore Germination.

    Directory of Open Access Journals (Sweden)

    Kelly A Fimlaid

    2015-10-01

    Full Text Available Clostridium difficile is a Gram-positive spore-forming pathogen and a leading cause of nosocomial diarrhea. C. difficile infections are transmitted when ingested spores germinate in the gastrointestinal tract and transform into vegetative cells. Germination begins when the germinant receptor CspC detects bile salts in the gut. CspC is a subtilisin-like serine pseudoprotease that activates the related CspB serine protease through an unknown mechanism. Activated CspB cleaves the pro-SleC zymogen, which allows the activated SleC cortex hydrolase to degrade the protective cortex layer. While these regulators are essential for C. difficile spores to outgrow and form toxin-secreting vegetative cells, the mechanisms controlling their function have only been partially characterized. In this study, we identify the lipoprotein GerS as a novel regulator of C. difficile spore germination using targeted mutagenesis. A gerS mutant has a severe germination defect and fails to degrade cortex even though it processes SleC at wildtype levels. Using complementation analyses, we demonstrate that GerS secretion, but not lipidation, is necessary for GerS to activate SleC. Importantly, loss of GerS attenuates the virulence of C. difficile in a hamster model of infection. Since GerS appears to be conserved exclusively in related Peptostreptococcaeace family members, our results contribute to a growing body of work indicating that C. difficile has evolved distinct mechanisms for controlling the exit from dormancy relative to B. subtilis and other spore-forming organisms.

  9. New formulations on the finite element method for boundary value problems with internal/external boundary layers; Novas formulacoes de elementos finitos para problemas de valor de contorno com camadas limite interna/externa

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Luis Carlos Martins

    1998-06-15

    New Petrov-Galerkin formulations on the finite element methods for convection-diffusion problems with boundary layers are presented. Such formulations are based on a consistent new theory on discontinuous finite element methods. Existence and uniqueness of solutions for these problems in the new finite element spaces are demonstrated. Some numerical experiments shows how the new formulation operate and also their efficacy. (author)

  10. The effect of salt stress on the germination of maize (Zea mays L. seeds and photosynthetic pigments

    Directory of Open Access Journals (Sweden)

    Sali ALIU

    2015-11-01

    Full Text Available The objective of this study was to investigate the effect of salinity stress on seed germination and chlorophyll content in maize. In the study, two maize hybrids were included (Bc 678 and Bc 408 originating from the Bc Institute at Rugvica near Zagreb (Croatia and two maize populations (LMP-1 and LMP-2 originating from Kosovo. The experiment was conducted in four replicates of 100 seeds, which were germinated on top of double-layered papers, each with 10 ml of salt solution of NaCl and CaCl2 in Petri dishes. Germinated seeds were counted every 24 h for 15 days. The photosynthetic pigments, chlorophylls ‘a’ and ‘b’ as well as carotenoids were extracted with 80 % acetone. Chlorophyll and carotenoid contents were calculated using absorbance values at 662, 644 and 440 nm. The effects of the NaCl and CaCl2 concentrations accounted for a high proportion of the variance in all analyses. The results showed that both germination percentage and germination index decreased significantly in all cultivars at the highest salt concentrations. The significant differences between different concentrations of salinity were also found in all cultivars for the content of chlorophyll ‘a’ and ‘b’ and for the content of carotenoids.

  11. Seed germination of Sierra Nevada postfire chaparral species

    Science.gov (United States)

    Keeley, Jon E.; McGinnis, Thomas W.; Bollens, Kim A.

    2005-01-01

    The California chaparral community has a rich flora of species with different mechanisms for cuing germination to postfire conditions. Here we report further germination experiments that elucidate the response of several widespread shrub species whose germination response was not clear and include other species from the Sierra Nevada, which have not previously been included in germination studies. The shrubs Adenostoma fasciculatum and Eriodictyon crassifolium and the postfire annualMentzelia dispersa exhibited highly significant germination in response to smoke treatments, with some enhanced germination in response to heating as well. The shrubs Fremontodendron californicum and Malacothamnus fremontii were stimulated only by heat-shock treatments. Seeds buried in the soil for one year exhibited substantially higher germination for controls and most treatments. In the case of two postfire annuals, Mimulus bolanderi and M. gracilipes, germination of fresh seed was significantly greater with smoke or heating but after soil storage, over two-thirds of the control seeds germinated and treatment effects were not significant. These two annuals are generally restricted to postfire conditions and it is suggested that control germination of soil-stored seed may be a light-response (which was not tested here) as previously reported for another chaparral species in that genus.

  12. Elucidating the germination transcriptional program using small molecules.

    Science.gov (United States)

    Bassel, George W; Fung, Pauline; Chow, Tsz-fung Freeman; Foong, Justin A; Provart, Nicholas J; Cutler, Sean R

    2008-05-01

    The transition from seed to seedling is mediated by germination, a complex process that starts with imbibition and completes with radicle emergence. To gain insight into the transcriptional program mediating germination, previous studies have compared the transcript profiles of dry, dormant, and germinating after-ripened Arabidopsis (Arabidopsis thaliana) seeds. While informative, these approaches did not distinguish the transcriptional responses due to imbibition, shifts in metabolism, or breaking of dormancy from those triggered by the initiation of germination. In this study, three mechanistically distinct small molecules that inhibit Arabidopsis seed germination (methotrexate, 2, 4-dinitrophenol, and cycloheximide) were identified using a small-molecule screen and used to probe the germination transcriptome. Germination-responsive transcripts were defined as those with significantly altered transcript abundance across all inhibitory treatments with respect to control germinating seeds, using data from ATH1 microarrays. This analysis identified numerous germination regulators as germination responsive, including the DELLA proteins GAI, RGA, and RGL3, the abscisic acid-insensitive proteins ABI4, ABI5, ABI8, and FRY1, and the gibberellin receptor GID1A. To help visualize these and other publicly available seed microarray data, we designed a seed mRNA expression browser using the electronic Fluorescent Pictograph platform. An overall decrease in gene expression and a 5-fold greater number of transcripts identified as statistically down-regulated in drug-inhibited seeds point to a role for mRNA degradation or turnover during seed germination. The genes identified in our study as responsive to germination define potential uncharacterized regulators of this process and provide a refined transcriptional signature for germinating Arabidopsis seeds.

  13. Spore germination, early development and some notes on the effects of in vitro culture medium on Frullania ericoides (Nees Mont. (Frullaniaceae, Marchantiophyta

    Directory of Open Access Journals (Sweden)

    Juliana da Costa Silva-e-Costa

    Full Text Available ABSTRACT In bryophytes, establishment can occur by a sexual or asexual process, but the production of spores enables colonization of a wider range of habitats and substrates than can asexual propagules. Successful germination is critical for establishment in a new environment. This paper addresses germination and sporeling development in Frullania ericoides, a leafy liverwort species. Fresh spores were inoculated in vitro in different culture strengths of Knop’s nutrient solution (one-fourth strength, half strength, full strength, one and a half strength and double strength, in order to evaluate the effects of this solution on spore germination and on the development of external protonema. On the first assessment, spore germination was observed at all the concentrations. Germination was endosporic, with cell division and proliferation, resulting in a globular protonema, within the spore wall. Beginning at the fourth week, the development of tightly concave primordial leaves was observed in all but the double-strength medium. Throughout the period of study, the treatments with lower concentrations exhibited external protonema with greater lengths. The double-strength treatment was statistically different from other treatments in at least two parameters. The results of this study demonstrate the potential of in vitro culture techniques for bryophyte spore studies and germplasm preservation.

  14. Spatio-temporal profiling and degradation of alpha-amylase isozymes during barley seed germination

    DEFF Research Database (Denmark)

    Bak-Jensen, K.S.; Laugesen, Sabrina; Østergaard, Ole

    2007-01-01

    Ten genes from two multigene families encode barley alpha-amylases. To gain insight into the occurrence and fate of individual isoforms during seed germination, the alpha-amylase repertoire was mapped by using a proteomics approach consisting of 2D gel electrophoresis, western blotting, and mass...... increased during germination. Assessing the fragment minimum chain length by peptide mass fingerprinting suggested that alpha-amylase 2 ( gi vertical bar 4699831) initially was cleaved just prior to domain B that protrudes from the (beta alpha)(8)-barrel between beta-strand 3 and alpha-helix 3, followed...... by cleavage on the C-terminal side of domain B and near the C-terminus. Only two shorter fragments were identified of the other alpha-amylase 2 (gi vertical bar 166985). The 2D gels of dissected tissues showed alpha-amylase degradation to be confined to endosperm. In contrast, the aleurone layer contained...

  15. Gene Expression Profile Changes in Germinating Rice

    Institute of Scientific and Technical Information of China (English)

    Dongli He; Chao Han; Pingfang Yang

    2011-01-01

    Water absorption is a prerequisite for seed germination.During imbibition,water influx causes the resumption of many physiological and metabolic processes in growing seed.In order to obtain more complete knowledge about the mechanism of seed germination,two-dimensional gel electrophoresis was applied to investigate the protein profile changes of rice seed during the first 48 h of imbibition.Thirtynine differentially expressed proteins were identified,including 19 down-regulated and 20 up-regulated proteins.Storage proteins and some seed development- and desiccation-associated proteins were down regulated.The changed patterns of these proteins indicated extensive mobilization of seed reserves.By contrast,catabolism-associated proteins were up regulated upon imbibition.Semi-quantitative real time polymerase chain reaction analysis showed that most of the genes encoding the down- or upregulated proteins were also down or up regulated at mRNA level.The expression of these genes was largely consistent at mRNA and protein levels.In providing additional information concerning gene regulation in early plant life,this study will facilitate understanding of the molecular mechanisms of seed germination.

  16. A rice lectin receptor-like kinase that is involved in innate immune responses also contributes to seed germination.

    Science.gov (United States)

    Cheng, Xiaoyan; Wu, Yan; Guo, Jianping; Du, Bo; Chen, Rongzhi; Zhu, Lili; He, Guangcun

    2013-11-01

    Seed germination and innate immunity both have significant effects on plant life spans because they control the plant's entry into the ecosystem and provide defenses against various external stresses, respectively. Much ecological evidence has shown that seeds with high vigor are generally more tolerant of various environmental stimuli in the field than those with low vigor. However, there is little genetic evidence linking germination and immunity in plants. Here, we show that the rice lectin receptor-like kinase OslecRK contributes to both seed germination and plant innate immunity. We demonstrate that knocking down the OslecRK gene depresses the expression of α-amylase genes, reducing seed viability and thereby decreasing the rate of seed germination. Moreover, it also inhibits the expression of defense genes, and so reduces the resistance of rice plants to fungal and bacterial pathogens as well as herbivorous insects. Yeast two-hybrid and co-immunoprecipitation experiments revealed that OslecRK interacts with an actin-depolymerizing factor (ADF) in vivo via its kinase domain. Moreover, the rice adf mutant exhibited a reduced seed germination rate due to the suppression of α-amylase gene expression. This mutant also exhibited depressed immune responses and reduced resistance to biotic stresses. Our results thus provide direct genetic evidence for a common physiological pathway connecting germination and immunity in plants. They also partially explain the common observation that high-vigor seeds often perform well in the field. The dual effects of OslecRK may be indicative of progressive adaptive evolution in rice.

  17. Some physicochemical properties of flour from germinated sorghum grain.

    Science.gov (United States)

    Elkhalifa, Abd Elmoneim O; Bernhardt, Rita

    2013-02-01

    A Sudanese sorghum cultivar (Fetarita) was germinated for 3 days. Stability and clarity of sorghum pastes, freeze-thaw stability, gel consistency, and swelling power were measured every 24 h. There is no substantial difference in stability and clarity between flour samples from germinated and ungerminated sorghum, but a different behavior was observed between samples stored at room temperature and at 4 °C. Cooked paste derived from germinated sorghum flour presented higher syneresis than that derived from ungerminated sorghum flour over the first three cycles but when the cycle number increased, both flours showed zero syneresis value. For the gel consistency the flours derived from germinated sorghum produced thinnest gels. The neutral and acid gel consistency increased when the germination time increased. Germination had not much effect on the swelling power of sorghum flour.

  18. Effects of graphene on seed germination and seedling growth

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ming; Gao, Bin, E-mail: bg55@ufl.edu [University of Florida, Department of Agricultural and Biological Engineering (United States); Chen, Jianjun [University of Florida, Department of Environmental Horticulture and Mid-Florida Research & Education Center (United States); Li, Yuncong [University of Florida, Soil and Water Science Department Tropical Research & Education Center (United States)

    2015-02-15

    The environmental impact of graphene has recently attracted great attention. In this work, we show that graphene at a low concentration affected tomato seed germination and seedling growth. Graphene-treated seeds germinated much faster than control seeds. Analytical results indicated that graphene penetrated seed husks. The penetration might break the husks to facilitate water uptake, resulting in faster germination and higher germination rates. At the stage of seedling growth, graphene was also able to penetrate root tip cells. Seedlings germinated from graphene-treated seeds had slightly lower biomass accumulation than the control, but exhibited significantly longer stems and roots than the control, which suggests that graphene, in contrast with other nanoparticles, had different effects on seedling growth. Taken together, our results imply that graphene played complicated roles in affecting the initial stage of seed germination and subsequent seedling growth.

  19. Germination and outgrowth of spores of Bacillus cereus group members: diversity and role of germinant receptors.

    Science.gov (United States)

    Abee, Tjakko; Groot, Masja Nierop; Tempelaars, Marcel; Zwietering, Marcel; Moezelaar, Roy; van der Voort, Menno

    2011-04-01

    Bacillus cereus is a gram-positive, facultative anaerobic, endospore-forming toxicogenic human pathogen. Endospores are highly specialized, metabolically dormant cell types that are resistant to extreme environmental conditions, including heat, dehydration and other physical stresses. B. cereus can enter a range of environments, and can in its spore form, survive harsh conditions. If these conditions become favorable, spores can germinate and grow out and reach considerable numbers in a range of environments including processed foods. Certainly the last decade, when consumer preferences have shifted to mildly processed food, new opportunities arose for spore-forming spoilage and pathogenic organisms. Only rigorous methods have been shown to be capable of destroying all spores present in food, thus a shift toward e.g., milder heat preservation strategies, may result in low but significant amounts of viable spores in food products. Hence, the need for a mild spore destruction strategy is eminent including control of spore outgrowth. Consequently, there is a large interest in triggering spore germination in foodstuffs, since germinated spores have lost the extreme resistance of dormant spores and are relatively easy to kill. Another option could be to prevent germination so that no dangerous levels can be reached. This contribution will focus on germination and outgrowth characteristics of B. cereus and other members of the B. cereus group, providing an overview of the niches these spore-formers can occupy, the signals that trigger germination, and how B. cereus copes with these wake-up calls in different environments including foods, during food processing and upon interaction with the human host.

  20. Proteomic analyses of apoplastic proteins from germinating Arabidopsis thaliana pollen

    OpenAIRE

    Ge, Weina; Song, Yun; Zhang, Cuijun; Zhang, Yafang; Burlingame, Alma L; Guo, Yi

    2011-01-01

    Pollen grains play important roles in the reproductive processes of flowering plants. The roles of apoplastic proteins in pollen germination and in pollen tube growth are comparatively less well understood. To investigate the functions of apoplastic proteins in pollen germination, the global apoplastic proteins of mature and germinated Arabidopsis thaliana pollen grains were prepared for differential analyses by using 2-dimensional fluorescence difference gel electrophoresis (2-D DIGE) satura...

  1. The relation of morphology and affinity maturation in germinal centers

    CERN Document Server

    Meyer-Hermann, M

    2002-01-01

    The specific morphology of germinal centers is analyzed in the context of the optimization of the humoral immune response. The relevance of dark and light zones for the affinity maturation process is investigated in the framework of a theoretical model for the germinal center reaction. Especially, it is shown that an intermediate appearance of dark zones in germinal center reactions is advantageous for the process of antibody optimization.

  2. Design of a Typical Offshore Transportation System for External Corrosion

    Directory of Open Access Journals (Sweden)

    Shittu, A. A

    2016-07-01

    Full Text Available The external corrosion assessment of a typical offshore transportation system has been presented. Cathodic protection design was carried out for the pipeline and it was found that a bracelet square weld on anode of L = 195, G =101.6 , Thickness = 70, M = 149.75 , ∅ = 1.2235, N = 128 and s = 300was found to be satisfactory in providing secondary/ backup protection for the 48inchespipeline in the external environment provided. The external anticorrosion coating selected is the Three layer polyethylene (3LPE coating based on the dimensions of the pipeline and the design temperature of 80℃. The 3LPE external corrosioncoating will comprise of an inner layer fusion bond epoxy, a middle layer: adhesive and an outer layer: High density polyethylene (HDPE base with additives.

  3. Evolution of 'smoke' induced seed germination in pyroendemic plants

    Science.gov (United States)

    Keeley, J. E.; Pausas, J.G.

    2016-01-01

    Pyroendemics are plants in which seedling germination and successful seedling recruitment are restricted to immediate postfire environments. In many fire-prone ecosystems species cue their germination to immediate postfire conditions. Here we address how species have evolved one very specific mechanism, which is using the signal of combustion products from biomass. This is often termed ‘smoke’ stimulated germination although it was first discovered in studies of charred wood effects on germination of species strictly tied to postfire conditions (pyroendemics). Smoke stimulated germination has been reported from a huge diversity of plant species. The fact that the organic compound karrikin (a product of the degradation of cellulose) is a powerful germination cue in many species has led to the assumption that this compound is the only chemical responsible for smoke-stimulated germination. Here we show that smoke-stimulated germination is a complex trait with different compounds involved. We propose that convergent evolution is a more parsimonious model for smoke stimulated germination, suggesting that this trait evolved multiple times in response to a variety of organic and inorganic chemical triggers in smoke. The convergent model is congruent with the evolution of many other fire-related traits.

  4. Glutathione synthesis is essential for pollen germination in vitro

    Science.gov (United States)

    2011-01-01

    Background The antioxidant glutathione fulfills many important roles during plant development, growth and defense in the sporophyte, however the role of this important molecule in the gametophyte generation is largely unclear. Bioinformatic data indicate that critical control enzymes are negligibly transcribed in pollen and sperm cells. Therefore, we decided to investigate the role of glutathione synthesis for pollen germination in vitro in Arabidopsis thaliana accession Col-0 and in the glutathione deficient mutant pad2-1 and link it with glutathione status on the subcellular level. Results The depletion of glutathione by buthionine sulfoximine (BSO), an inhibitor of glutathione synthesis, reduced pollen germination rates to 2-5% compared to 71% germination in wildtype controls. The application of reduced glutathione (GSH), together with BSO, restored pollen germination and glutathione contents to control values, demonstrating that inhibition of glutathione synthesis is responsible for the decrease of pollen germination in vitro. The addition of indole-3-acetic acid (IAA) to media containing BSO restored pollen germination to control values, which demonstrated that glutathione depletion in pollen grains triggered disturbances in auxin metabolism which led to inhibition of pollen germination. Conclusions This study demonstrates that glutathione synthesis is essential for pollen germination in vitro and that glutathione depletion and auxin metabolism are linked in pollen germination and early elongation of the pollen tube, as IAA addition rescues glutathione deficient pollen. PMID:21439079

  5. Evolution of Externally Excited Convective Cells in Plasmas

    DEFF Research Database (Denmark)

    Sugai, H.; Juul Rasmussen, Jens; Thomsen, Kenneth

    1983-01-01

    Convective cells are excited externally in a fully ionized magnetized plasma, and their space-time evolution is investigated by two-dimensional potential measurements. A positive cell is excited externally in the `scrape-off' layer of a plasma column produced by surface ionization. Its interaction...

  6. Externally Verifiable Oblivious RAM

    Directory of Open Access Journals (Sweden)

    Gancher Joshua

    2017-04-01

    Full Text Available We present the idea of externally verifiable oblivious RAM (ORAM. Our goal is to allow a client and server carrying out an ORAM protocol to have disputes adjudicated by a third party, allowing for the enforcement of penalties against an unreliable or malicious server. We give a security definition that guarantees protection not only against a malicious server but also against a client making false accusations. We then give modifications of the Path ORAM [15] and Ring ORAM [9] protocols that meet this security definition. These protocols both have the same asymptotic runtimes as the semi-honest original versions and require the external verifier to be involved only when the client or server deviates from the protocol. Finally, we implement externally verified ORAM, along with an automated cryptocurrency contract to use as the external verifier.

  7. External Beam Therapy (EBT)

    Science.gov (United States)

    ... Esophageal Cancer Treatment Head and Neck Cancer Treatment Lung Cancer Treatment Prostate Cancer Treatment Brain Tumor Treatment Why is ... Radiation Oncology) Breast Cancer Treatment Esophageal Cancer Treatment Lung Cancer Treatment Images related to External Beam Therapy (EBT) Sponsored ...

  8. MALIGNANT EXTERNAL OTITIS

    OpenAIRE

    Massoud Moghaddam

    1993-01-01

    Two case reports of malignant external otitis in the elderly diabetics and their complications and management with regard to our experience at Amir Alam Hospital, Department of ENT will be discussed here.

  9. Checklists for external validity

    DEFF Research Database (Denmark)

    Dyrvig, Anne-Kirstine; Kidholm, Kristian; Gerke, Oke;

    2014-01-01

    RATIONALE, AIMS AND OBJECTIVES: The quality of the current literature on external validity varies considerably. An improved checklist with validated items on external validity would aid decision-makers in judging similarities among circumstances when transferring evidence from a study setting...... to an implementation setting. In this paper, currently available checklists on external validity are identified, assessed and used as a basis for proposing a new improved instrument. METHOD: A systematic literature review was carried out in Pubmed, Embase and Cinahl on English-language papers without time restrictions....... The retrieved checklist items were assessed for (i) the methodology used in primary literature, justifying inclusion of each item; and (ii) the number of times each item appeared in checklists. RESULTS: Fifteen papers were identified, presenting a total of 21 checklists for external validity, yielding a total...

  10. Migration with fiscal externalities.

    Science.gov (United States)

    Hercowitz, Z; Pines, D

    1991-11-01

    "This paper analyses the distribution of a country's population among regions when migration involves fiscal externalities. The main question addressed is whether a decentralized decision making [by] regional governments can produce an optimal population distribution...or a centralized intervention is indispensable, as argued before in the literature.... It turns out that, while with costless mobility the fiscal externality is fully internalized by voluntary interregional transfers, with costly mobility, centrally coordinated transfers still remain indispensable for achieving the socially optimal allocation."

  11. Sen cycles and externalities

    OpenAIRE

    Piggins, Ashley; Salerno, Gillian

    2016-01-01

    It has long been understood that externalities of some kind are responsible for Sen’s (1970) theorem on the impossibility of a Paretian liberal. However, Saari and Petron (2006) show that for any social preference cycle generated by combining the weak Pareto principle and individual decisiveness, every decisive individual must suffer at least one strong negative externality. We show that this fundamental result only holds when individual preferences are strict. Building on their contribution,...

  12. Allelopathy of aqueous leaf extracts from the invasive alien tree Pittosporum undulatum on germination and growth of barnyard grass

    Directory of Open Access Journals (Sweden)

    Fernando Bertol Carpanezzi

    2014-09-01

    Full Text Available Barnyard grass (Echinochloa crusgalli (L. P. Beauv. is a herbicide-resistant weed that brings negative impacts to rice crops and threatens floodplains biodiversity worldwide. This study aimed to investigate allelopathic influences of extracts from Pittosporum undulatum Vent. (cheesewood leaves on barnyard grass. Leachates in concentrations of 20%, 15%, 10%, 5% and 2.5% (w/v, aqueous extracts from powdered leached and non-leached leaves (10%, 7,5%, 5%, 2.5% and 1.25% for both, coumarin solution at 0.6 mM and original Roundup ® in concentration according to the label information were prepared. Petri-dishes germination bioassays, with counting at each 12 hours, allowed to determinate both germinability and germination rate; polyethylene glycol (PEG 6000 solutions were prepared to evaluate osmotic effects. In growth tests, seedlings were exposed for seven days, when root and shoot lengths were measured. Germination was sensitive to extracts from powdered leaves. In regard to growth, roots showed dose-dependent length reduction and necrosis. Inhibitory effects from different aqueous extracts suggest action of both internal and external leaf allelochemicals, raising the possibility of Pittosporum undulatum use for barnyard grass control.

  13. Effect of temperature and pre-germination treatments on seed germination and seedling vigor of Jatropha curcas L

    Directory of Open Access Journals (Sweden)

    Thais Cremon

    2012-09-01

    Full Text Available To date, there are no official methods used to test the seed germination of physic nut (Jatropha curcas and there have only been a few attempts to optimize the germination of this species. The objective of this study was to evaluate the effect of different temperatures and pre-germination treatments on the germination and seedling vigor of J. curcas. The treatments were arranged in a completely randomized factorial scheme with four temperatures (20, 25, 30 and 20-30°C x two types of seeds (with and without the seed tegument x six periods of water imbibition (0, 6, 12, 18, 24 and 30h. The seeds were sown using a roller system with four replications of 50 seeds for each treatment. The germination percentage was higher for seeds stored at 25°C, when the seed tegument was maintained. When the time of water imbibition was increased, the germination percentage decreased, as well as the index of germination velocity and the percentage of germination of the first count. Imbibition for up to 12h led to an increase in hypocotyl growth. For this species, the maximum germination potential and highest vigor were obtained at 25°C, for seeds with teguments that were maintained and were not submitted to water imbibition.

  14. Impact of sorbic acid on germinant receptor-dependent and -independent germination pathways in Bacillus cereus

    NARCIS (Netherlands)

    Melis, van C.C.J.; Nierop Groot, M.N.; Abee, T.

    2011-01-01

    Amino acid- and inosine-induced germination of Bacillus cereus ATCC 14579 spores was reversibly inhibited in the presence of 3 mM undissociated sorbic acid. Exposure to high hydrostatic pressure, Ca-dipicolinic acid (DPA), and bryostatin, an activator of PrkC kinase, negated this inhibition,

  15. Dynamics of B cells in germinal centres.

    Science.gov (United States)

    De Silva, Nilushi S; Klein, Ulf

    2015-03-01

    Humoral immunity depends on the germinal centre (GC) reaction during which somatically mutated high-affinity memory B cells and plasma cells are generated. Recent studies have uncovered crucial cues that are required for the formation and the maintenance of GCs and for the selection of high-affinity antibody mutants. In addition, it is now clear that these events are promoted by the dynamic movements of cells within and between GCs. These findings have resolved the complexities of the GC reaction in greater detail than ever before. This Review focuses on these recent advances and discusses their implications for the establishment of humoral immunity.

  16. Serine carboxypeptidase 46 Regulates Grain Filling and Seed Germination in Rice (Oryza sativa L.)

    Science.gov (United States)

    Li, Zhiyong; Tang, Liqun; Qiu, Jiehua; Zhang, Wen; Wang, Yifeng; Tong, Xiaohong; Wei, Xiangjin; Hou, Yuxuan

    2016-01-01

    Serine carboxypeptidase (SCP) is one of the largest groups of enzymes catalyzing proteolysis for functional protein maturation. To date, little is known about the function of SCPs in rice. In this study, we present a comprehensive analysis of the gene structure and expression profile of 59 rice SCPs. SCP46 is dominantly expressed in developing seeds, particularly in embryo, endosperm and aleurone layers, and could be induced by ABA. Functional characterization revealed that knock-down of SCP46 resulted in smaller grain size and enhanced seed germination. Furthermore, scp46 seed germination became less sensitive to the ABA inhibition than the Wild-type did; suggesting SCP46 is involved in ABA signaling. As indicated by RNA-seq and qRT-PCR analysis, numerous grain filling and seed dormancy related genes, such as SP, VP1 and AGPs were down-regulated in scp46. Yeast-two-hybrid assay also showed that SCP46 interacts with another ABA-inducible protein DI19-1. Taken together, we suggested that SCP46 is a master regulator of grain filling and seed germination, possibly via participating in the ABA signaling. The results of this study shed novel light into the roles of SCPs in rice. PMID:27448032

  17. Serine carboxypeptidase 46 Regulates Grain Filling and Seed Germination in Rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Zhiyong Li

    Full Text Available Serine carboxypeptidase (SCP is one of the largest groups of enzymes catalyzing proteolysis for functional protein maturation. To date, little is known about the function of SCPs in rice. In this study, we present a comprehensive analysis of the gene structure and expression profile of 59 rice SCPs. SCP46 is dominantly expressed in developing seeds, particularly in embryo, endosperm and aleurone layers, and could be induced by ABA. Functional characterization revealed that knock-down of SCP46 resulted in smaller grain size and enhanced seed germination. Furthermore, scp46 seed germination became less sensitive to the ABA inhibition than the Wild-type did; suggesting SCP46 is involved in ABA signaling. As indicated by RNA-seq and qRT-PCR analysis, numerous grain filling and seed dormancy related genes, such as SP, VP1 and AGPs were down-regulated in scp46. Yeast-two-hybrid assay also showed that SCP46 interacts with another ABA-inducible protein DI19-1. Taken together, we suggested that SCP46 is a master regulator of grain filling and seed germination, possibly via participating in the ABA signaling. The results of this study shed novel light into the roles of SCPs in rice.

  18. Environmental external effects from wind power based on the EU ExternE methodology

    DEFF Research Database (Denmark)

    Ibsen, Liselotte Schleisner; Nielsen, Per Sieverts

    1998-01-01

    The European Commission has launched a major study project, ExternE, to develop a methodology to quantify externalities. A “National Implementation Phase”, was started under the Joule II programme with the purpose of implementing the ExternE methodology in all member states. The main objective...

  19. Osmopriming duration in Araçá-boi seeds germination

    Directory of Open Access Journals (Sweden)

    Marcela Liege da Silva

    2016-06-01

    Full Text Available The Araca-boi is a native fruit of the Amazon region and its fruits have great potential for agro-industrial use due to the intrinsic characteristics of the pulp. The seeds are dormant and the primary cause could be due to the presence of inhibiting chemicals germination and can also be caused by the impermeability in tegument. The objective of this study was to assess the osmopriming efficiency promoted by Sucrose (C12H22O11 and Potassium Nitrate (KNO3 on germination of seeds of araca-boi in different immersion times. Thus, the seeds were osmoconditioned in following solutions: C12H22O11, KNO3 , KNO3 + C12H22O11 and H2 O, by period of 6, 12 and 24 h. Throughout of 70 days were evaluated the germination percentage and germination rate (index. The experiment is based on a completely randomized in a factorial analysis 4x3 with four replications of 10 seeds. The osmopriming of Araca-boi seed in KNO3 solution was shown to be efficient both to promote germination and the germination rate. The Araca-boi seeds osmoconditioned in KNO3 solution has an average efficiency of 99% in the germination percentage up to 70 days. The osmopriming period showed no influence on seed germination of the seeds of Araca-boi.

  20. Temperature and substrate on Plukenetia volubilis L. seed germination

    Directory of Open Access Journals (Sweden)

    Givanildo Z. da Silva

    Full Text Available ABSTRACT The objective of this work was to evaluate the effect of temperature and substrate on the germination of P. volubilis seeds. Seeds harvested from 25 matrix plants were submitted, in two studies, to conditions of (i sowing in rolled paper towel at the temperatures of 10, 15, 20, 25, 30, 35, 40, and 45 °C, for the evaluation of germination, first count of germination, germination speed index and mean time for germination, and (ii sowing in the substrates paper towel, sand, Bioplant®, Bioplant® and micron, superfine, fine, medium and coarse vermiculite. The same evaluations mentioned in the first study were conducted at the temperature of 30 oC, as well as plant growth. The treatment replicates were distributed in a completely randomized block design and the effects of temperature were compared by polynomial regression analysis. The substrates were compared by the Scott-Knott test at 0.05 probability level. The data show that the ideal range of temperature for the germination of P. volubilis is between 25 and 30 °C. The temperature of 20 °C is the minimum for germination and those above 35 °C are lethal to these seeds. The most favorable substrate for P. volubilis seed germination is micron or fine vermiculite.

  1. Investigating the Influence of Karrikins on Seed Germination

    Science.gov (United States)

    de Beer, Josef

    2012-01-01

    Recent research has identified a karrikin (a butenolide derative) known as 3-methyl-2H-furo[2,3-c]pyran-2-one, formed from burning cellulose, that stimulates seed germination. Here, I present ideas on how to investigate the influence of karrikins on seed germination in the laboratory.

  2. Radish (Raphanus sativus) seed size affects germination response to coumarin

    Science.gov (United States)

    The inhibition of seed germination by an allelochemical is generally greater in small seeds than in large seeds. Studies reporting these results used a large number of plant species that varied in seed size, which might have introduced differences in germination characteristics or various parameter...

  3. Investigating the Influence of Karrikins on Seed Germination

    Science.gov (United States)

    de Beer, Josef

    2012-01-01

    Recent research has identified a karrikin (a butenolide derative) known as 3-methyl-2H-furo[2,3-c]pyran-2-one, formed from burning cellulose, that stimulates seed germination. Here, I present ideas on how to investigate the influence of karrikins on seed germination in the laboratory.

  4. Germinal center reaction: antigen affinity and presentation explain it all.

    Science.gov (United States)

    Oropallo, Michael A; Cerutti, Andrea

    2014-07-01

    The selection and expansion of B cells undergoing affinity maturation in the germinal center is a hallmark of humoral immunity. A recent paper in Nature provides new insights into the relationships between the affinity of the immunoglobulin receptor for antigen, the ability of B cells to present antigen to T cells, and the processes of selection, mutation, and clonal expansion in the germinal center.

  5. Role of ethylene in the germination metabolism of ricinus communis

    Science.gov (United States)

    Cristescu, Simona; Dumitras, Dan C.; Godeanu, Adriana

    1999-03-01

    A CO2 laser-based photoacoustic method has been used to monitor the ethylene (C2H4) released by castor bean (Ricinus communis) seeds during germination. The relationship between the evolution of the C2H4 germinating seeds and the respiration intensity is presented.

  6. Coffee (Coffea arabica cv. Rubi) seed germination : mechanism and regulation

    NARCIS (Netherlands)

    Silva, da E.A.A.

    2002-01-01

     Coffee seeds display slow and variable germination which severely hampers the production of seedlings for planting in the following growth season. Little work has been done with the aim to understand the behavior of coffee seeds during germination and there is a

  7. Dynamic Proteomic Insights of Seed Germination

    Institute of Scientific and Technical Information of China (English)

    Marc Galland; Romain Huguet; Erwann Arc; Gwendal Cueff; Dominique Job; Lo(i)c Rajjou

    2012-01-01

    Proteome analysis,which involves the identification and characterization of expressed proteins,is a powerful tool for determining the biological roles and functions of individual proteins.Furthermore,by providing a systematic and without any a priori mean for large-scale identification of cellular proteins,proteomics is expected to accelerate discoveries in complex processes such as plant development.Our research activity is mainly focused on the "Functional proteomics" approach in the field of seed biology.We are developing a proteome analysis of the model plant,Arabidopsis thaliana,in order to investigate seed development,dormancy,germination and longevity and identify related changes in the seed proteome.Combined approaches associating classical 2D gel-based proteome and dynamic radiolabeled proteome disclosed data regarding protein turnover and protein stability (http://www.seed-proteome.com).The selective translation of mRNAs emerges as an important mechanism regulating molecular functions involved in the control of seed germination.

  8. Mitochondrial biogenesis in plants during seed germination.

    Science.gov (United States)

    Law, Simon R; Narsai, Reena; Whelan, James

    2014-11-01

    Mitochondria occupy a central role in the eukaryotic cell. In addition to being major sources of cellular energy, mitochondria are also involved in a diverse range of functions including signalling, the synthesis of many essential organic compounds and a role in programmed cell death. The active proliferation and differentiation of mitochondria is termed mitochondrial biogenesis and necessitates the coordinated communication of mitochondrial status within an integrated cellular network. Two models of mitochondrial biogenesis have been defined previously, the growth and division model and the maturation model. The former describes the growth and division of pre-existing mature organelles through a form of binary fission, while the latter describes the propagation of mitochondria from structurally and biochemically simple promitochondrial structures that upon appropriate stimuli, mature into fully functional mitochondria. In the last decade, a number of studies have utilised seed germination in plants as a platform for the examination of the processes occurring during mitochondrial biogenesis. These studies have revealed many new aspects of the tightly regulated procession of events that define mitochondrial biogenesis during this period of rapid development. A model for mitochondrial biogenesis that supports the maturation of mitochondria from promitochondrial structures has emerged, where mitochondrial signalling plays a crucial role in the early steps of seed germination.

  9. Growth hormone induces multiplication of the slowly cycling germinal cells of the rat tibial growth plate.

    OpenAIRE

    Ohlsson, C.; Nilsson, A; Isaksson, O; Lindahl, A

    1992-01-01

    To study the effect of locally infused growth hormone (GH) or insulin-like growth factor I(IGF-I) on slowly cycling cells in the germinal cell layer of the tibial growth plate, osmotic minipumps delivering 14.3 microCi of [3H]thymidine per day were implanted s.c. into hypophysectomized rats, and GH (1 microgram) or IGF-I (10 micrograms) was injected daily through a cannula implanted in the proximal tibia. The opposite leg served as a control. After 12 days of treatment, the osmotic minipumps ...

  10. Starch bioengineering affects cereal grain germination and seedling establishment

    DEFF Research Database (Denmark)

    Shaik, Shahnoor Sultana; Carciofi, Massimiliano; Martens, Helle Juel;

    2014-01-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule...... structure, and not only the endosperm starch content per se, is important for germination and seedling establishment. For that purpose, wild-type (WT), and specifically engineered degradable hyperphosphorylated (HP) starch and more resistant amylose-only (AO) starch barley lines were used. The transgenics...... showed no severe phenotypes and the WT and HP lines degraded the starch similarly, having 30% residual starch after 12 d of germination. However, the AO line showed significant resistance to degradation, having 57% residual starch. Interestingly, protein and β-glucan (BG) degradation was stimulated...

  11. Evaluation of homeopathy in seed germination of yellow ipe

    Directory of Open Access Journals (Sweden)

    Naira Maranhão Silva

    2014-09-01

    Full Text Available Studies with homeopathie on seed germination of native forest species are scarce, regardless of its potential as low impact technology. Therefore, the objective of this study was to evaluate the use of homeopathic medications in different dynamizations in the seed germination of yellow ipe. The experimental design was completely randomized with three replications, in a factorial scheme with the three medicines in five dynamizations, totaling 16 treatments with the control consisting of distilled water. The medications used were Calcarea carbonica, Carbo vegetabilis and Silicea. The mediations were applied in of 6, 12, 30, 100 and 200 centesimals hahnemanianas (CH dynamizations. Regarding germination percentage and speed of germination index the medicament Silicea in 12CH dynamization was less efficient when compared to others medications and dynamizations. The use of homeopathic preparations does not benefit the pattern of yellow ipe seeds germination.

  12. Stromal networking: cellular connections in the germinal centre.

    Science.gov (United States)

    Denton, Alice E; Linterman, Michelle A

    2017-03-17

    Secondary lymphoid organs are organized into distinct zones, governed by different types of mesenchymal stromal cells. These stromal cell subsets are critical for the generation of protective humoral immunity because they direct the migration of, and interaction between, multiple immune cell types to form the germinal centre. The germinal centre response generates long-lived antibody-secreting plasma cells and memory B cells which can provide long-term protection against re-infection. Stromal cell subsets mediate this response through control of immune cell trafficking, activation, localization and antigen access within the secondary lymphoid organ. Further, distinct populations of stromal cells underpin the delicate spatial organization of immune cells within the germinal centre. Because of this, the interactions between immune cells and stromal cells in secondary lymphoid organs are fundamental to the germinal centre response. Herein we review how this unique relationship leads to effective germinal centre responses.

  13. Coordination of seed dormancy and germination processes by MYB96.

    Science.gov (United States)

    Lee, Kyounghee; Seo, Pil Joon

    2015-01-01

    The transition between seed dormancy and germination is an important stage that initiates plant life cycle. Hormonal balances of abscisic acid (ABA) and gibberellin (GA) contribute to determining the proper timing to germinate. Here, we demonstrate that the R2R3-type MYB96 transcription factor, a key ABA signaling mediator, coordinates seed dormancy and germination processes through distinct downstream events. This transcription factor controls ABA-INSENSITIVE 4 (ABI4) expression to inhibit seed germination by suppressing breakdown of lipid reserves in embryo. In addition, it also induces seed dormancy by stimulating ABA biosynthesis in an ABI4-independent manner. We propose that MYB96 integrates a multitude of environmental stress signals and acts as a master regulator in the determination of timing for seed germination.

  14. Externality or sustainability economics?

    Energy Technology Data Exchange (ETDEWEB)

    Bergh, Jeroen C.J.M. van den [ICREA, Barcelona (Spain); Department of Economics and Economic History and Institute for Environmental Science and Technology, Universitat Autonoma de Barcelona (Spain)

    2010-09-15

    In an effort to develop 'sustainability economics' Baumgaertner and Quaas (2010) neglect the central concept of environmental economics-'environmental externality'. This note proposes a possible connection between the concepts of environmental externality and sustainability. In addition, attention is asked for other aspects of 'sustainability economics', namely the distinction weak/strong sustainability, spatial sustainability and sustainable trade, distinctive sustainability policy, and the ideas of early 'sustainability economists'. I argue that both sustainability and externalities reflect a systems perspective and propose that effective sustainability solutions require that more attention is given to system feedbacks, notably other-regarding preferences and social interactions, and energy and environmental rebound. The case of climate change and policy is used to illustrate particular statements. As a conclusion, a list of 20 insights and suggestions for research is offered. (author)

  15. Metasurface external cavity laser

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Luyao, E-mail: luyaoxu.ee@ucla.edu; Curwen, Christopher A.; Williams, Benjamin S. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, California 90095 (United States); Hon, Philip W. C.; Itoh, Tatsuo [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Chen, Qi-Sheng [Northrop Grumman Aerospace Systems, Redondo Beach, California 90278 (United States)

    2015-11-30

    A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

  16. In-Situ Fabrication of a Self-Aligned Selective Emitter Silicon Solar Cell Using the Gold Top Contacts To Facilitate the Synthesis of a Nanostructured Black Silicon Antireflective Layer Instead of an External Metal Nanoparticle Catalyst.

    Science.gov (United States)

    Lu, Yen-Tien; Barron, Andrew R

    2015-06-10

    Silicon solar cells with nanopore-type black silicon (b-Si) antireflection (AR) layers and self-aligned selective emitter (SE) are reported in which the b-Si structure is prepared without the traditional addition of a nanoparticle (NP) catalyst. The contact-assisted chemical etching (CACE) method is reported here for the first time, in which the metal top contacts on silicon solar cell surfaces function as the catalysts for b-Si fabrication and the whole etching process can be done in minutes at room temperature. The CACE method is based on the metal-assisted chemical etching (MACE) solution but without or metal precursor in the Si etchant (HF:H2O2:H2O), and the Au top contacts, or catalysts, are not removed from the solar cell surface after the etching. The effects of etching time, HF and H2O2 concentration, and the HF:H2O2 ratio on the b-Si morphology, surface reflectivity, and solar cell efficiency have been investigated. Higher [HF] and [H2O2] with longer etching time cause collapse of the b-Si nanoporous structure and penetration of the p-n junctions, which are detrimental to the solar cell efficiency. The b-Si solar cell fabricated with the HF:H2O2:H2O volume ratio of 3:3:20 and a 3 min etch time shows the highest efficiency 8.99% along with a decrease of reflectivity from 36.1% to 12.6% compared to that of the nonetched Si solar cell.

  17. Pre-treating Seed to Enhance Germination of Desert Shrubs

    Energy Technology Data Exchange (ETDEWEB)

    W. K. Ostler; D. C. Anderson; D. J. Hansen

    2002-06-01

    Creosotebush [Larrea tridentata (D.C.) Cav.] and white bursage [Ambrosia dumosa (A. Gray) W.W. Payne] seeds were subjected to pre-treatments of rinsing and soaking in water and thiourea to enhance germination in laboratory experiments. The effects of darkness, temperature, seed source, and soil moisture were also evaluated in the laboratory. The best pre-treatment from the laboratory experiments, rinsing with water for 36 hours followed by drying, was field-tested at Fort Irwin, California. Two sites and two seeding dates (early March and mid April) were determined for each site. Five mulch treatments (no mulch, straw, gravel, chemical stabilizer, and plastic) were evaluated in combination with the seed pre-treatments. Field emergence was greatly enhanced with the seed pre-treatment for white bursage during the March (18-42% increase in germination) and April seedings (16-23% increase in germination). Creosotebush showed poor germination during March (2-5%) when soil temperatures averaged 15 C, but germination increased during the April trials (6-43%) when soil temperatures averaged 23 C. The seed pre-treatment during the April trials increased germination from 16-23%. The plastic mulch treatment increased germination dramatically during both the March and April trials. The plastic mulch increased soil temperatures (8-10 C)and maintained high humidity during germination. Both the chemical stabilizer and the gravel mulches improved germination over the control while the straw mulch decreased germination. These results suggest that seed pre-treatments combined with irrigation and mulch are effective techniques to establish these two dominant Mojave Desert species from seed.

  18. Association mapping of soybean seed germination under salt stress.

    Science.gov (United States)

    Kan, Guizhen; Zhang, Wei; Yang, Wenming; Ma, Deyuan; Zhang, Dan; Hao, Derong; Hu, Zhenbin; Yu, Deyue

    2015-12-01

    Soil salinity is a serious threat to agriculture sustainability worldwide. Seed germination is a critical phase that ensures the successful establishment and productivity of soybeans in saline soils. However, little information is available regarding soybean salt tolerance at the germination stage. The objective of this study was to identify the genetic mechanisms of soybean seed germination under salt stress. One natural population consisting of 191 soybean landraces was used in this study. Soybean seeds produced in four environments were used to evaluate the salt tolerance at their germination stage. Using 1142 single-nucleotide polymorphisms (SNPs), the molecular markers associated with salt tolerance were detected by genome-wide association analysis. Eight SNP-trait associations and 13 suggestive SNP-trait associations were identified using a mixed linear model and the TASSEL 4.0 software. Eight SNPs or suggestive SNPs were co-associated with two salt tolerance indices, namely (1) the ratio of the germination index under salt conditions to the germination index under no-salt conditions (ST-GI) and (2) the ratio of the germination rate under salt conditions to the germination rate under no-salt conditions (ST-GR). One SNP (BARC-021347-04042) was significantly associated with these two traits (ST-GI and ST-GR). In addition, nine possible candidate genes were located in or near the genetic region where the above markers were mapped. Of these, five genes, Glyma08g12400.1, Glyma08g09730.1, Glyma18g47140.1, Glyma09g00460.1, and Glyma09g00490.3, were verified in response to salt stress at the germination stage. The SNPs detected could facilitate a better understanding of the genetic basis of soybean salt tolerance at the germination stage, and the marker BARC-021347-04042 could contribute to future breeding for soybean salt tolerance by marker-assisted selection.

  19. Analysis of germination capacity and germinant receptor (sub)clusters of genomesequenced Bacillus cereus environmental isolates and model strains

    NARCIS (Netherlands)

    Warda, Alicja K.; Xiao, Yinghua; Boekhorst, Jos; Wells-Bennik, Marjon H.J.; Nierop Groot, Masja N.; Abee, Tjakko

    2017-01-01

    Spore germination of 17 Bacillus cereus food isolates and reference strains was evaluated using flow cytometry analysis in combination with fluorescent staining at a single-spore level. This approach allowed for rapid collection of germination data under more than 20 conditions, including heat ac

  20. Effects of nitrogen ion implantation on lily pollen germination and the distribution of the actin cytoskeleton during pollen germination

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effects of low energy nitrogen ion implantation on lily (Lilium davidii Duch.) pollen germination and the distribution of the actin cytoskeleton during pollen germination have been studied. Preliminary results showed that the ratio of pollen germination increased from (16.0±1.6)% to (27.0±2.1)% when implanted with nitrogen ions by 100 keV and a dose of 1013 ions/cm2. Further experiments were performed by staining the actin filaments in pollen with rhodamine-phalloidin and detected by using laser confocol microscopy. After hydration for 10 h, the actin filaments in ion implanted pollen grains tended to form thick bundles oriented in parallel or ring shape at the germinal furrow, indicating that the effect of nitrogen ion implantation on the germination of pollen might be mediated by reorganization of the actin cytoskeleton.

  1. Analysis of Natural Allelic Variation Controlling Arabiciopsis thaliana Seed Germinability in Response to Cold and Dark: Identification of Three Major Quantitative Trait Loci

    Institute of Scientific and Technical Information of China (English)

    Ping-Hong Meng; Audrey Macquet; Olivier Loudet; Annie Marion-Poll; Helen M.North

    2008-01-01

    Light and temperature are key external factors in the control of Arabidopsis thaliana seed germination and dormancy mechanisms. Perception and response to these stimuli have to ensure that seedling emergence and growth occur at the most advantageous time for correct establishment. Analysis of over 300 Arabidopsis accessions identified 14, from 12 different geographical locations, that were able to germinate to greater than 20% at 6℃ in the dark. This natural variation was exploited to identify genetic loci responsible for cold-tolerant, dark germination. A quantitative trait loci approach was used on recombinant inbred line progeny of a cross between Bay-0 and Shahdara. Six distinct quantitative trait loci were identified, three of which were major loci, each responsible for 17-25% of the phenotypic variability in this trait. Parental phenotypes indicated that the majority of the cold-tolerant, dark-germination characteristics are related to light responses. Validation of the three major loci using heterogeneous inbred families confirmed the feasibility of fine mapping and cloning the genes at the quantitative trait loci responsible for cold-tolerant, dark germination.

  2. Mobilization of lipid reserves during germination of oat (Avena sativa L.), a cereal rich in endosperm oil.

    Science.gov (United States)

    Leonova, Svetlana; Grimberg, Asa; Marttila, Salla; Stymne, Sten; Carlsson, Anders S

    2010-06-01

    Since the cereal endosperm is a dead tissue in the mature grain, beta-oxidation is not possible there. This raises the question about the use of the endosperm oil in cereal grains during germination. In this study, mobilization of lipids in different tissues of germinating oat grains was analysed using thin-layer and gas chromatography. The data imply that the oat endosperm oil [triacylglycerol (TAG)] is not a dead-end product as it was absorbed by the scutellum, either as free fatty acids (FFAs) released from TAG or as intact TAG immediately degraded to FFAs. These data were supported by light and transmission electron microscopy (LM and TEM) studies where close contact between endosperm lipid droplets and the scutellum was observed. The appearance of the fused oil in the oat endosperm changed into oil droplets during germination in areas close to the aleurone and the scutellar epithelium. However, according to the data obtained by TEM these oil droplets are unlikely to be oil bodies surrounded by oleosins. Accumulation of FFA pools in the embryo suggested further transport of FFAs from the scutellum. Noticeably high levels of TAG were also accumulated in the embryo but were not synthesized by re-esterification from imported FFAs. Comparison between two oat cultivars with different amounts of oil and starch in the endosperm suggests that an increased oil to starch ratio in oat grains does not significantly impact the germination process.

  3. Live Cell Imaging During Germination Reveals Dynamic Tubular Structures Derived from Protein Storage Vacuoles of Barley Aleurone Cells

    Directory of Open Access Journals (Sweden)

    Verena Ibl

    2014-09-01

    Full Text Available The germination of cereal seeds is a rapid developmental process in which the endomembrane system undergoes a series of dynamic morphological changes to mobilize storage compounds. The changing ultrastructure of protein storage vacuoles (PSVs in the cells of the aleurone layer has been investigated in the past, but generally this involved inferences drawn from static pictures representing different developmental stages. We used live cell imaging in transgenic barley plants expressing a TIP3-GFP fusion protein as a fluorescent PSV marker to follow in real time the spatially and temporally regulated remodeling and reshaping of PSVs during germination. During late-stage germination, we observed thin, tubular structures extending from PSVs in an actin-dependent manner. No extensions were detected following the disruption of actin microfilaments, while microtubules did not appear to be involved in the process. The previously-undetected tubular PSV structures were characterized by complex movements, fusion events and a dynamic morphology. Their function during germination remains unknown, but might be related to the transport of solutes and metabolites.

  4. Live Cell Imaging During Germination Reveals Dynamic Tubular Structures Derived from Protein Storage Vacuoles of Barley Aleurone Cells.

    Science.gov (United States)

    Ibl, Verena; Stoger, Eva

    2014-01-01

    The germination of cereal seeds is a rapid developmental process in which the endomembrane system undergoes a series of dynamic morphological changes to mobilize storage compounds. The changing ultrastructure of protein storage vacuoles (PSVs) in the cells of the aleurone layer has been investigated in the past, but generally this involved inferences drawn from static pictures representing different developmental stages. We used live cell imaging in transgenic barley plants expressing a TIP3-GFP fusion protein as a fluorescent PSV marker to follow in real time the spatially and temporally regulated remodeling and reshaping of PSVs during germination. During late-stage germination, we observed thin, tubular structures extending from PSVs in an actin-dependent manner. No extensions were detected following the disruption of actin microfilaments, while microtubules did not appear to be involved in the process. The previously-undetected tubular PSV structures were characterized by complex movements, fusion events and a dynamic morphology. Their function during germination remains unknown, but might be related to the transport of solutes and metabolites.

  5. Stochastic Control - External Models

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad

    2005-01-01

    This note is devoted to control of stochastic systems described in discrete time. We are concerned with external descriptions or transfer function model, where we have a dynamic model for the input output relation only (i.e.. no direct internal information). The methods are based on LTI systems...

  6. Productivity Change and Externalities

    DEFF Research Database (Denmark)

    Kravtsova, Victoria

    2014-01-01

    firms and the economy as a whole. The approach used in the current research accounts for different internal as well as external factors that individual firms face and evaluates the effect on changes in productivity, technology as well as the efficiency of domestic firms. The empirical analysis focuses...... change in different types of firms and sectors of the economy...

  7. Multiple external root resorption.

    Science.gov (United States)

    Yusof, W Z; Ghazali, M N

    1989-04-01

    Presented is an unusual case of multiple external root resorption. Although the cause of this resorption was not determined, several possibilities are presented. Trauma from occlusion, periodontal and pulpal inflammation, and resorption of idiopathic origin are all discussed as possible causes.

  8. Temporaly germinating rhythms of moss Funaria hygrometrica Hedw. spores

    Science.gov (United States)

    Pundiak, O.; Demkiv, O.

    The process of an organism development is regular and gradual. These characteristics of the development are especially evident in archegonial plants. It was shown that spores of moss Funar ia hygrometrica Hedw. in Knop's nutrient medium with 0,2% glucose in the dark in vertical orientation of Petry dishes, germinated polarly depending on gravity direction. At the begining, the primary rhyziod developed being usually directed downwards and then after 24 hours primary chloronema developed growing usually upwards. The amyloplasts sedimentation was shown before the rhyzoid and chloronema formation. It determines not only the time, but spatial orientation of the primary rhyzoid and chloronema (Pundjak at al., 2001). EGTA in concentration of 510- 5 M inhibited the initiation of the primary rhyzoid. The primary chloronema developed as usual in 48 h after the spores sowing. Temporary cooling caused analogical effect. Basing on these results we drew the conclusion that the primary rhyzoid and chloronema differently react on the action of EGTA and the cooling. The primary chloronema was more tolerant then the rhyzoid and maintained its usual gravisensitivy. Thus, we can think that EGTA and the cooling stop the development of primary rhyzoid, but it does not disturb physiological rhythm which underlais in the base of the function of the biological clock. The stability of biological rhythms and their indeterminism in respect of described above external and internal factors is real thanks to dissipation, which makes considerable interval of uncertainties of distributions of distances between segments of biopolymers and thus, of their fermentative activities (Pundjak,2001). Therefore the rise of biological clocks of each organism is in certain sense transcendental.

  9. Proteome analysis of Norway maple (Acer platanoides L. seeds dormancy breaking and germination: influence of abscisic and gibberellic acids

    Directory of Open Access Journals (Sweden)

    Pawłowski Tomasz A

    2009-05-01

    Full Text Available Abstract Background Seed dormancy is controlled by the physiological or structural properties of a seed and the external conditions. It is induced as part of the genetic program of seed development and maturation. Seeds with deep physiological embryo dormancy can be stimulated to germinate by a variety of treatments including cold stratification. Hormonal imbalance between germination inhibitors (e.g. abscisic acid and growth promoters (e.g. gibberellins is the main cause of seed dormancy breaking. Differences in the status of hormones would affect expression of genes required for germination. Proteomics offers the opportunity to examine simultaneous changes and to classify temporal patterns of protein accumulation occurring during seed dormancy breaking and germination. Analysis of the functions of the identified proteins and the related metabolic pathways, in conjunction with the plant hormones implicated in seed dormancy breaking, would expand our knowledge about this process. Results A proteomic approach was used to analyse the mechanism of dormancy breaking in Norway maple seeds caused by cold stratification, and the participation of the abscisic (ABA and gibberellic (GA acids. Forty-four proteins showing significant changes were identified by mass spectrometry. Of these, eight spots were identified as water-responsive, 18 spots were ABA- and nine GA-responsive and nine spots were regulated by both hormones. The classification of proteins showed that most of the proteins associated with dormancy breaking in water were involved in protein destination. Most of the ABA- and GA-responsive proteins were involved in protein destination and energy metabolism. Conclusion In this study, ABA was found to mostly down-regulate proteins whereas GA up-regulated proteins abundance. Most of the changes were observed at the end of stratification in the germinated seeds. This is the most active period of dormancy breaking when seeds pass from the quiescent

  10. Effect of different germination conditions on antioxidative properties and bioactive compounds of germinated brown rice.

    Science.gov (United States)

    Lin, You-Tung; Pao, Cheng-Cheng; Wu, Shwu-Tzy; Chang, Chi-Yue

    2015-01-01

    This study investigates antioxidative activity and bioactive compounds of ungerminated brown rice (UBR) and germinated brown rice (GBR). We used two rice cultivars (Oryza sativa L.), Taiwan Japonica 9 (TJ-9) and Taichung Indica 10 (TCI-10), as the materials in our experiments. The conditions for inducing germination are soaking time in water 24, 48, or 72 h; temperature 26 or 36°C; incubation in light or darkness; and open or closed vessels, in which the antioxidative activities and bioactive compounds of GBR were determined. We found that, in order to maximize antioxidative activity and bioactive compounds, germination should be under higher temperature (36°C), long soaking time (72 h), darkness, and closed vessel. GBR contains much higher levels of antioxidative activity and bioactive compounds than ungerminated brown rice (UBR). We found a strong correlation between antioxidative activities (DPPH radical scavenging ability, reducing power, and Trolox equivalent antioxidant capacity) and bioactive compounds (γ-oryzanols, tocopherol, and tocotrienol). Higher temperature (36°C) is also conducive to the production of GABA in GBR. These results are considered very useful research references for the development of future functional foods and additives.

  11. In vitro culture and germination of terrestrial Asian orchid seeds.

    Science.gov (United States)

    Lee, Yung-I

    2011-01-01

    Orchidaceae is one of the largest families of flowering plants, and many of its species are highly valuable as herbal medicines and to the horticultural industry. To meet commercial requirements and to conserve natural resources, in vitro seed germination has been utilized to produce large quantities of uniform seedlings. In general, terrestrial orchid seeds are more difficult to germinate and grow than epiphytic orchids. Terrestrial orchid seeds have a hardened seed coat and more stringent requirements for germination in vitro. In this chapter, we document the timing of seed collection and pretreatments for improving in vitro germination of some terrestrial Asian orchids. The process of in vitro germination is demonstrated, including (1) the culture of immature seeds; (2) the culture of mature seeds; and (3) subsequent seedling development. For immature seed culture, optimal timing of seed harvest is key to maximizing germination; for mature seed culture, selection of adequate pretreatment conditions (i.e., the duration and concentrations of pretreatment solutions) is essential to improve germination.

  12. Proteomic analyses of apoplastic proteins from germinating Arabidopsis thaliana pollen.

    Science.gov (United States)

    Ge, Weina; Song, Yun; Zhang, Cuijun; Zhang, Yafang; Burlingame, Alma L; Guo, Yi

    2011-12-01

    Pollen grains play important roles in the reproductive processes of flowering plants. The roles of apoplastic proteins in pollen germination and in pollen tube growth are comparatively less well understood. To investigate the functions of apoplastic proteins in pollen germination, the global apoplastic proteins of mature and germinated Arabidopsis thaliana pollen grains were prepared for differential analyses by using 2-dimensional fluorescence difference gel electrophoresis (2-D DIGE) saturation labeling techniques. One hundred and three proteins differentially expressed (p value≤0.01) in pollen germinated for 6h compared with un-germination mature pollen, and 98 spots, which represented 71 proteins, were identified by LC-MS/MS. By bioinformatics analysis, 50 proteins were identified as secreted proteins. These proteins were mainly involved in cell wall modification and remodeling, protein metabolism and signal transduction. Three of the differentially expressed proteins were randomly selected to determine their subcellular localizations by transiently expressing YFP fusion proteins. The results of subcellular localization were identical with the bioinformatics prediction. Based on these data, we proposed a model for apoplastic proteins functioning in pollen germination and pollen tube growth. These results will lead to a better understanding of the mechanisms of pollen germination and pollen tube growth.

  13. T-cell subsets in the germinal center.

    Science.gov (United States)

    Ramiscal, Roybel R; Vinuesa, Carola G

    2013-03-01

    T cells are known to migrate to B-cell-enriched follicles and germinal centers within secondary lymphoid organs to provide help to B cells. Cognate T:B interactions that take place at the T:B border and subsequently within germinal centers are essential for B-cell priming, differentiation into germinal center B cells, and selection of mutated cells into memory B cells or memory plasma cells. In recent years, different stages of maturation within B-cell helper T cells, collectively known as B-follicular helper T (Tfh) cells, as well as heterogeneity amid germinal center T cells are becoming clear. Indeed, germinal centers support not only bona fide Tfh cells but also CD4(+) and CD8(+) follicular regulatory T (Tfr) cells that act to suppress germinal center responses and B-cell helper natural killer T cells. There is a growing need for more precise phenotypic and functional distinction of these specialized T-cell subsets. In this review, we summarize current knowledge on the ontogeny, molecular identity, and functional relevance of the various subsets of germinal center T cells.

  14. Involvement of Alternative Splicing in Barley Seed Germination.

    Science.gov (United States)

    Zhang, Qisen; Zhang, Xiaoqi; Wang, Songbo; Tan, Cong; Zhou, Gaofeng; Li, Chengdao

    2016-01-01

    Seed germination activates many new biological processes including DNA, membrane and mitochondrial repairs and requires active protein synthesis and sufficient energy supply. Alternative splicing (AS) regulates many cellular processes including cell differentiation and environmental adaptations. However, limited information is available on the regulation of seed germination at post-transcriptional levels. We have conducted RNA-sequencing experiments to dissect AS events in barley seed germination. We identified between 552 and 669 common AS transcripts in germinating barley embryos from four barley varieties (Hordeum vulgare L. Bass, Baudin, Harrington and Stirling). Alternative 3' splicing (34%-45%), intron retention (32%-34%) and alternative 5' splicing (16%-21%) were three major AS events in germinating embryos. The AS transcripts were predominantly mapped onto ribosome, RNA transport machineries, spliceosome, plant hormone signal transduction, glycolysis, sugar and carbon metabolism pathways. Transcripts of these genes were also very abundant in the early stage of seed germination. Correlation analysis of gene expression showed that AS hormone responsive transcripts could also be co-expressed with genes responsible for protein biosynthesis and sugar metabolisms. Our RNA-sequencing data revealed that AS could play important roles in barley seed germination.

  15. Studies on the molecular mechanisms of seed germination.

    Science.gov (United States)

    Han, Chao; Yang, Pingfang

    2015-05-01

    Seed germination that begins with imbibition and ends with radicle emergence is the first step for plant growth. Successful germination is not only crucial for seedling establishment but also important for crop yield. After being dispersed from mother plant, seed undergoes continuous desiccation in ecosystem and selects proper environment to trigger germination. Owing to the contribution of transcriptomic, proteomic, and molecular biological studies, molecular aspect of seed germination is elucidated well in Arabidopsis. Recently, more and more proteomic and genetic studies concerning cereal seed germination were performed on rice (Oryza sativa) and barley (Hordeum vulgare), which possess completely different seed structure and domestication background with Arabidopsis. In this review, both the common features and the distinct mechanisms of seed germination are compared among different plant species including Arabidopsis, rice, and maize. These features include morphological changes, cell and its related structure recovery, metabolic activation, hormone behavior, and transcription and translation activation. This review will provide more comprehensive insights into the molecular mechanisms of seed germination.

  16. Evolution of nutrient ingredients in tartary buckwheat seeds during germination.

    Science.gov (United States)

    Yiming, Zhou; Hong, Wang; Linlin, Cui; Xiaoli, Zhou; Wen, Tang; Xinli, Song

    2015-11-01

    Evolution of nutrient components and the antioxidative activity of seed sprouts of tartary buckwheat (Fagopyrum tataricum L. Gaertn) were investigated in the course of germination. Results showed that the contents of total flavonoids increased with germination time and leveled off after the third germination day with the changing trend of rutin and quercetin opposite to each other. The decrease of total protein and total sugar contents in the germinated seeds was accompanied respectively by an increase of amino acid and reducing sugar contents. The contents of vitamin C (Vc) and B1(V(B1)) exhibited a minimum with no appreciable changes found for vitamin B(2) (V(B2)) and B(6) (V(B6)). The contents of total chlorophyll, chlorophyll A and B all exhibited a maximum on the fifth germination day. The contents of fatty acids had no regular changing trend with germination time. The free radical-scavenging activities of the seeds increased with germination time and were caused by an increase in their antioxidative activity.

  17. External-field-free magnetic biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuanpeng; Wang, Yi; Klein, Todd; Wang, Jian-Ping, E-mail: jpwang@umn.edu [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2014-03-24

    In this paper, we report a magnetic nanoparticle (MNP) detection scheme without the presence of any external magnetic field. The proposed magnetic sensor uses a patterned groove structure within the sensor so that no external magnetic field is needed to magnetize the MNPs. An example is given based on a giant magnetoresistance (GMR) sensing device with a spin valve structure. For this structure, the detection of MNPs located inside the groove and near the free layer is demonstrated under no external magnetic field. Micromagnetic simulations are performed to calculate the signal to noise level of this detection scheme. A maximum signal to noise ratio (SNR) of 18.6 dB from one iron oxide magnetic nanoparticle with 8 nm radius is achieved. As proof of concept, this external-field-free GMR sensor with groove structure of 200 nm × 200 nm is fabricated using a photo and an electron beam integrated lithography process. Using this sensor, the feasibility demonstration of the detection SNR of 9.3 dB is achieved for 30 μl magnetic nanoparticles suspension (30 nm iron oxide particles, 1 mg/ml). This proposed external-field-free sensor structure is not limited to GMR devices and could be applicable to other magnetic biosensing devices.

  18. Germination traits of three weed species in Kosovo

    Directory of Open Access Journals (Sweden)

    A. Mehmeti

    2010-02-01

    Full Text Available Amaranthus retroflexus, Echinochloa crus-galli and Datura stramonium are the most important weed species in Kosovo. They cause severe yield depression, contaminate fodder and negatively affect growth and reproduction of other weed species. To counteract these problems, specific strategies need to be developed. Such strategies should consider information on species germination traits. In this context, our study provides information on temperature requirements for germination. Seeds of A. retroflexus, E. crus-galli and D. stramonium were harvested in two sub-regions of Kosovo (western and eastern parts differing in climate and land use. They were set for germination experiments in growth chambers at temperatures ranging from 3 to 35 °C and under field conditions. In both experiments, the germination rate differed between species and provenances. In the growth chamber experiment, germination of all three species was negligible below 15 °C and reached the highest rates between 24 and 30 °C. Seeds originating from the western part of Kosovo had higher germination rates and required a lower temperature for germination than seeds originating from the eastern part. In the field experiment, the time-dependent germination behaviour of D. stramonium differed between provenances. In general, germination started when soil temperature was above 18 °C and continued as long as the soil was moist. The results are discussed in the context of the need to develop weed management strategies against these weeds in Kosovo.

  19. Effect of synthetic detergents on germination of fern spores

    Energy Technology Data Exchange (ETDEWEB)

    Devi, Y.; Devi, S.

    1986-12-01

    Synthetic detergents constitute one of the most important water pollutants by contaminating the lakes and rivers through domestic and industrial use. Considerable information is now available for the adverse effects of detergents an aquatic fauna including fish, algae, and higher aquatic plants. Marked inhibition of germination in orchids and brinjals and of seedlings growth in raddish suggest that rapidly growing systems could be sensitive to detergent polluted water. The present study of the effect of linear alkyl benzene sulphonate on germination of the spores of a fern, Diplazium esculentum aims at the understanding of the effects of water pollution on pteridophytes and the development of spore germination assay for phytoxicity evaluation.

  20. Germination of myxospores from the fruiting bodies of Myxococcus xanthus.

    OpenAIRE

    Otani, M.; Inouye, M; Inouye, S

    1995-01-01

    Germination of myxospores from fruiting bodies of Myxococcus xanthus was examined under a light microscope as well as by analyzing the incorporation of [3H]uracil into the RNA fraction. Efficient germination was observed in 0.2% Casitone containing 8 mM MgSO4 and 1 mM CaCl2 at 30 degrees C. Under this condition, spherical myxospores were converted into rod-shaped vegetative cells within 5 to 6 h. The germination was severely inhibited in the presence of 1 mM phenylmethylsulfonyl fluoride, a p...

  1. ExternE transport methodology for external cost evaluation of air pollution

    DEFF Research Database (Denmark)

    Jensen, S. S.; Berkowicz, R.; Brandt, J.

    The report describes how the human exposure estimates based on NERI's human exposure modelling system (AirGIS) can improve the Danish data used for exposure factors in the ExternE Transport methodology. Initially, a brief description of the ExternE Tranport methodology is given and it is summaris...

  2. The External Mind

    DEFF Research Database (Denmark)

    The External Mind: an Introduction by Riccardo Fusaroli, Claudio Paolucci pp. 3-31 The sign of the Hand: Symbolic Practices and the Extended Mind by Massimiliano Cappuccio, Michael Wheeler pp. 33-55 The Overextended Mind by Shaun Gallagher pp. 57-68 The "External Mind": Semiotics, Pragmatism......, Extended Mind and Distributed Cognition by Claudio Paolucci pp. 69-96 The Social Horizon of Embodied Language and Material Symbols by Riccardo Fusaroli pp. 97-123 Semiotics and Theories of Situated/Distributed Action and Cognition: a Dialogue and Many Intersections by Tommaso Granelli pp. 125-167 Building...... Action in Public Environments with Diverse Semiotic Resources by Charles Goodwin pp. 169-182 How Marking in Dance Constitutes Thinking with the Body by David Kirsh pp. 183-214 Ambiguous Coordination: Collaboration in Informal Science Education Research by Ivan Rosero, Robert Lecusay, Michael Cole pp. 215-240...

  3. External-Memory Multimaps

    CERN Document Server

    Angelino, Elaine; Mitzenmacher, Michael; Thaler, Justin

    2011-01-01

    Many data structures support dictionaries, also known as maps or associative arrays, which store and manage a set of key-value pairs. A \\emph{multimap} is generalization that allows multiple values to be associated with the same key. For example, the inverted file data structure that is used prevalently in the infrastructure supporting search engines is a type of multimap, where words are used as keys and document pointers are used as values. We study the multimap abstract data type and how it can be implemented efficiently online in external memory frameworks, with constant expected I/O performance. The key technique used to achieve our results is a combination of cuckoo hashing using buckets that hold multiple items with a multiqueue implementation to cope with varying numbers of values per key. Our external-memory results are for the standard two-level memory model.

  4. Seed germinating characteristics of 54 gramineous species in the alpine meadow on the eastern Qinghai-Tibet plateau

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The germination experiment was started on March 3,2004,and seeds were collected from July to October in 2003.We analyzed the percentage of germination,days to first germination,germination period and days to 50% germination.Among the 54 examined species,26 species exceeded 80% germination,11 species exceeded 60%-80% germination,8 exceeded 40%-0%,5 exceeded20%-40%,and 4 showed less than 20%.A principalcomponent analysis revealed that the species were distributed along two statistically independent axes,the first primarily represented the germination rate and the second represented the time of germination process.Based on scores of germination characteristics,duster analysis of the 54 gramineous species could be divided into 4 distinct groups:rapid,slow,intermediate germinating (germination percentage> 50%),and low germinating (germination percentage< 50%).The meaning of different groups to the vegetation regeneration was discussed.

  5. Effect of germination periods and hydrothermal treatments on in vitro protein and starch digestibility of germinated legumes.

    Science.gov (United States)

    Uppal, Veny; Bains, Kiran

    2012-04-01

    Germination of legumes followed by hydrothermal treatments is an effective mean of improving nutritive value of legumes. The protein content of mungbean, chickpea and cowpea increased by 9-11, 11-16 and 8-11% after germination. A significant (p ≤ 0.05) decrease in protein content was observed on pressure cooking and microwaving in all three legumes. The carbohydrates decreased by 1 to 3% during soaking and 2 to 6% during germination. A significant (p ≤ 0.05) improvement in in vitro protein digestibility (IVPD) was observed after soaking as well as after three germination periods. Germination resulted in an increase in IVPD from 15 to 25% in mungbean, 6 to 17% in chickpea and 6 to 17% in cowpea. A significant (p ≤ 0.05) increase in IVPD was observed when raw sprouts of three legumes were subjected to pressure cooking and microwaving. In vitro starch digestibility (IVSD) increased significantly (p ≤ 0.05) after germination, the percent increase being 8 to 12% in mungbean, 9 to 11% in chickpea and 10 to 13% in cowpea. The duration of germination had significant (p ≤ 0.05) effect on IVSD. A significant (p ≤ 0.05) improvement in IVSD was observed when legume sprouts were subjected to pressure cooking and microwave cooking.

  6. Germination of Croton urucurana L. seeds exposed to different storage temperatures and pre-germinative treatments

    Directory of Open Access Journals (Sweden)

    Silvana P.Q. Scalon

    2012-03-01

    Full Text Available The present work evaluated the germinability and vigor of Croton urucurana seeds. 1 Seeds were sorted by color (caramel, gray and black and were subjected to seven different pre-germination treatments followed by incubation at 20ºC, 25°C or 20/30°C. 2 Seeds were stored in cold chambers or at room temperature for up to 300 days and were subsequently incubated at 20/30ºC in a germination chamber or under greenhouse conditions. Only gray seeds showed significant germination rates. The highest first count percentages of total germination and the highest germination speed indices were observed in control seeds and in those which were treated with water or 200 mg. L-1 gibberellic acid for 12 hours. Seeds stored under refrigeration showed the highest values for all of the characteristics examined, as well as less electrical conductivity of the imbibing solution. Seedlings were more vigorous when seeds were stored for 300 days in a cold chamber. The seedlings production can be increased by incubating the seeds at alternating temperatures (20/30°C. The seeds do not need pre-germination treatments.O presente trabalho avaliou a germinação e vigor de sementes de Croton urucurana. 1 As sementes foram classificadas por cores (caramelo, cinza e preto e foram submetidas a sete diferentes tratamentos pré-germinativos seguidos de incubação a 20ºC, 25°C e 20/30°C. 2 As sementes foram armazenadas em câmaras frias ou em temperatura ambiente por até 300 dias e foram posteriormente incubadas a 20/30ºC em câmara de germinação ou em condições de estufa. Somente sementes cinza apresentaram taxas significativas de germinação. As maiores percentagens de primeira contagem de germinação total e os maiores índices de velocidade de germinação foram observados em sementes de controle e naquelas que foram tratadas com água ou 200 mg L-1 de ácido giberélico por 12 horas. Sementes armazenadas sob refrigeração apresentaram os maiores valores para

  7. ddressing constraints in propagation of Allanblackia spp. through seed sectioning and air layering

    OpenAIRE

    Ofori D A; Asomaning J M; Peprah T; Agyeman V K; Anjarwalla P; Tchoundjeu Z; Mowo J G; Jamnadass R

    2015-01-01

    Allanblackia species are indigenous to West, East and Central African regions with the potential of providing an alternative source of income for rural populations through sale of seed oil. The species therefore needs to be domesticated to support sustainable production of Allanblackia seed oil. Propagation of Allanblackia parviflora through seed germination and air layering was therefore undertaken. Stratified and non-stratified seeds or seed sections were germinated in sand, pla...

  8. YwdL in Bacillus cereus: its role in germination and exosporium structure.

    Directory of Open Access Journals (Sweden)

    Cassandra Terry

    Full Text Available In members of the Bacillus cereus group the outermost layer of the spore is the exosporium, which interacts with hosts and the environment. Efforts have been made to identify proteins of the exosporium but only a few have so far been characterised and their role in determining spore architecture and spore function is still poorly understood. We have characterised the exosporium protein, YwdL. ΔywdL spores have a more fragile exosporium, subject to damage on repeated freeze-thawing, although there is no evidence of altered resistance properties, and coats appear intact. Immunogold labelling and Western blotting with anti-YwdL antibodies identified YwdL to be located exclusively on the inner surface of the exosporium of B. cereus and B. thuringiensis. We conclude that YwdL is important for formation of a robust exosporium but is not required to maintain the crystalline assembly within the basal layer or for attachment of the hairy nap structure. ΔywdL spores are unable to germinate in response to CaDPA, and have altered germination properties, a phenotype that confirms the expected defect in localization of the cortex lytic enzyme CwlJ in the coat.

  9. Evolution, development, and initial function of the mammalian neocortex: response of the germinal zones to endothermy.

    Science.gov (United States)

    Smart, I H M

    2008-01-01

    In the mouse the release of neocortical neurons from the periventricular germinal layers of the forebrain commences towards the ventral margin of the lateral pallium at the level of the interventricular foramen and is propagated from there across the lateral wall of the hemisphere. In the adult cortex the origin of the gradient corresponded to the ventral portion of the somatotopic map of the body, that is, to the area representating structures derived from the embryonic branchial arches, namely, the peri-oral region and laryngo-pharyngeal masticatory apparatus. Branchial arch nerves also innervate the fore- and mid-gut and all the related exocrine and endocrine glands. This suggests that the mammalian neocortex evolved from a visceral integration area in a positionally equivalent area in the pallium of a reptilian ancestor which expanded in relation to extensive changes taking place in the visceral and branchial systems of the body during the transition from reptilian ectothermy to mammalian endothermy. The practical problem facing early mammals was to acquire and process the extra energy required to sustain a continuously high metabolic rate. Improvements to the food processing capabilities of the visceral and branchial systems and the expansion of their neural control were important components in the conglomerate of changes required to sustain the increased energy demands of endothermic tissues. Endothermy also bestowed the ability to sustain greater numbers of metabolically expensive neurons and this, in turn, required an appropriate response from the cell production mechanisms in the periventricular germinal layers.

  10. The Role of Aquaporins in pH-Dependent Germination of Rhizopus delemar Spores.

    Science.gov (United States)

    Turgeman, Tidhar; Shatil-Cohen, Arava; Moshelion, Menachem; Teper-Bamnolker, Paula; Skory, Christopher D; Lichter, Amnon; Eshel, Dani

    2016-01-01

    Rhizopus delemar and associated species attack a wide range of fruit and vegetables after harvest. Host nutrients and acidic pH are required for optimal germination of R. delemar, and we studied how this process is triggered. Glucose induced spore swelling in an acidic environment, expressed by an up to 3-fold increase in spore diameter, whereas spore diameter was smaller in a neutral environment. When suspended in an acidic environment, the spores started to float, indicating a change in their density. Treatment of the spores with HgCl2, an aquaporin blocker, prevented floating and inhibited spore swelling and germ-tube emergence, indicating the importance of water uptake at the early stages of germination. Two putative candidate aquaporin-encoding genes-RdAQP1 and RdAQP2-were identified in the R. delemar genome. Both presented the conserved NPA motif and six-transmembrane domain topology. Expressing RdAQP1 and RdAQP2 in Arabidopsis protoplasts increased the cells' osmotic water permeability coefficient (Pf) compared to controls, indicating their role as water channels. A decrease in R. delemar aquaporin activity with increasing external pH suggested pH regulation of these proteins. Substitution of two histidine (His) residues, positioned on two loops facing the outer side of the cell, with alanine eliminated the pH sensing resulting in similar Pf values under acidic and basic conditions. Since hydration is critical for spore switching from the resting to activate state, we suggest that pH regulation of the aquaporins can regulate the initial phase of R. delemar spore germination, followed by germ-tube elongation and host-tissue infection.

  11. New insights into the post-translational modification of multiple phosphoenolpyruvate carboxylase isoenzymes by phosphorylation and monoubiquitination during sorghum seed development and germination.

    Science.gov (United States)

    Ruiz-Ballesta, Isabel; Baena, Guillermo; Gandullo, Jacinto; Wang, Liqun; She, Yi-Min; Plaxton, William Charles; Echevarría, Cristina

    2016-05-01

    Phosphoenolpyruvate carboxylase (PEPC; E.C. 4.1.1.31) was characterized in developing and germinating sorghum seeds, focusing on the transcript and polypeptide abundance of multiple plant-type phosphoenolpyruvate carboxylase (PTPC) genes, and the post-translational modification of each isoenzyme by phosphorylation versus monoubiquitination during germination. We observed high levels of SbPPC4 (Sb07g014960) transcripts during early development (stage I), and extensive transcript abundance of SbPPC2 (Sb02g021090) and SbPPC3 (Sb04g008720) throughout the entire life cycle of the seed. Although tandem mass spectrometry (MS) analysis of immunopurified PTPC indicated that four different PTPC isoenzymes were expressed in the developing and germinating seeds, SbPPC3 was the most abundant isozyme of the developing seed, and of the embryo and the aleurone layer of germinating seeds. In vivo phosphorylation of the different PTPC isoenzymes at their conserved N-terminal seryl phosphorylation site during germination was also established by MS/MS analysis. Furthermore, three of the four isoenzymes were partially monoubiquitinated, with MS/MS pinpointing SbPPC2 and SbPPC3 monoubiquitination at the conserved Lys-630 and Lys-624 residues, respectively. Our results demonstrate that monoubiquitination and phosphorylation simultaneously occur in vivo with different PTPC isozymes during seed germination. In addition, we show that PTPC monoubiquitination in germinating sorghum seeds always increases at stage II (emergence of the radicle), is maintained during the aerobic period of rapid cell division and reserve mobilization, and remains relatively constant until stage IV-V when coleoptiles initiate the formation of the photosynthetic tissues.

  12. New insights into the post-translational modification of multiple phosphoenolpyruvate carboxylase isoenzymes by phosphorylation and monoubiquitination during sorghum seed development and germination

    Science.gov (United States)

    Ruiz-Ballesta, Isabel; Baena, Guillermo; Gandullo, Jacinto; Wang, Liqun; She, Yi-Min; Plaxton, William Charles; Echevarría, Cristina

    2016-01-01

    Phosphoenolpyruvate carboxylase (PEPC; E.C. 4.1.1.31) was characterized in developing and germinating sorghum seeds, focusing on the transcript and polypeptide abundance of multiple plant-type phosphoenolpyruvate carboxylase (PTPC) genes, and the post-translational modification of each isoenzyme by phosphorylation versus monoubiquitination during germination. We observed high levels of SbPPC4 (Sb07g014960) transcripts during early development (stage I), and extensive transcript abundance of SbPPC2 (Sb02g021090) and SbPPC3 (Sb04g008720) throughout the entire life cycle of the seed. Although tandem mass spectrometry (MS) analysis of immunopurified PTPC indicated that four different PTPC isoenzymes were expressed in the developing and germinating seeds, SbPPC3 was the most abundant isozyme of the developing seed, and of the embryo and the aleurone layer of germinating seeds. In vivo phosphorylation of the different PTPC isoenzymes at their conserved N-terminal seryl phosphorylation site during germination was also established by MS/MS analysis. Furthermore, three of the four isoenzymes were partially monoubiquitinated, with MS/MS pinpointing SbPPC2 and SbPPC3 monoubiquitination at the conserved Lys-630 and Lys-624 residues, respectively. Our results demonstrate that monoubiquitination and phosphorylation simultaneously occur in vivo with different PTPC isozymes during seed germination. In addition, we show that PTPC monoubiquitination in germinating sorghum seeds always increases at stage II (emergence of the radicle), is maintained during the aerobic period of rapid cell division and reserve mobilization, and remains relatively constant until stage IV–V when coleoptiles initiate the formation of the photosynthetic tissues. PMID:27194739

  13. Effect of germination periods and hydrothermal treatments on in vitro protein and starch digestibility of germinated legumes

    OpenAIRE

    Uppal, Veny; Bains, Kiran

    2011-01-01

    Germination of legumes followed by hydrothermal treatments is an effective mean of improving nutritive value of legumes. The protein content of mungbean, chickpea and cowpea increased by 9–11, 11–16 and 8–11% after germination. A significant (p ≤ 0.05) decrease in protein content was observed on pressure cooking and microwaving in all three legumes. The carbohydrates decreased by 1 to 3% during soaking and 2 to 6% during germination. A significant (p ≤ 0.05) improvement in in vitro protein di...

  14. Hungarian surveillance of germinal mutations. Lack of detectable increase in indicator conditions caused by germinal mutations following the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Czeizel, A. (National Inst. of Hygiene, Budapest (Hungary). Dept. of Human Genetics and Teratology)

    1989-07-01

    The Hungarian surveillance of germinal mutations is based on three indicator conditions seen in offspring, i.e., 15 sentinel anomalies, Down syndrome and component anomaly pairs of unidentified multiple congenital anomalies. It is an 'opportunistic program', because the necessary data are available from the Hungarian Congenital Malformation Registry. This system is described and the criteria of a good registry are summarized. The analysis of indicator conditions caused by germinal mutations did not reveal any measurable mutagenic effects in Hungary following the accident at the Chernobyl nuclear power plant. The pros and cons of germinal mutation surveillance are discussed. (orig.).

  15. Minimal invasive localization of the germinal disc in ovo for subsequent chicken sexing using optical coherence tomography

    Science.gov (United States)

    Burkhardt, Anke; Geissler, Stefan; Cimalla, Peter; Walther, Julia; Koch, Edmund

    2010-02-01

    Reason for using optical coherence tomography (OCT) to locate the germinal disc is the questionable and ethically alarming killing of male layer chickens because for the layer line only the females are necessary. To avoid this and to protect the animal rights, the sex of the fertilized chicken egg has to be determined as early as possible in the unincubated state. Because the information whether the chick becomes male or female can be found in the germinal disc an accurate localization for sexing is essential. The germinal disc is located somewhere on top of the yolk and has a diameter of approximately 4 - 5 mm. Different imaging methods like ultrasonography, 3D-X-ray micro computed tomography and magnetic resonance imaging were used for localization until now, but found to be impractical. The goal of this study is to prove if OCT can be a moderate approach for the precise in ovo localization. Because the eggshell is an impenetrable barrier for OCT and to minimize the penetration of germs a very small hole is placed in the eggshell and a fan-shaped optical scanning pattern is used.

  16. Germination of Chenopodium Album in Response to Microwave Plasma Treatment

    Institute of Scientific and Technical Information of China (English)

    Bo(z)ena (S)ER(A); Vitězslav STRA(NA)K; Michal (S)ER(Y); Milan TICH(Y); Petr (S)PATENKA

    2008-01-01

    The seeds of Lamb's Quarters (Chenopodium album agg.) were stimulated by low-pressure discharge. The tested seeds were exposed to plasma discharge for different time durations (from 6 minutes to 48 minutes). Germination tests were performed under specified laboratory conditions during seven days in five identical and completely independent experiments. Significant differences between the control and plasma-treated seeds were observed. The treated seeds showed structural changes on the surface of the seat coat. They germinated faster and their sprout accretion on the first day of seed germination was longer. Germination rate for the untreated seeds was 15% while it increased approximately three times (max 55%) for seeds treated by plasma from 12 minutes to 48 minutes.

  17. Germination of Chenopodium Album in Response to Microwave Plasma Treatment

    Science.gov (United States)

    Será, Bozena; Stranák, Vitezslav; Serý, Michal; Tichý, Milan; Spatenka, Petr

    2008-08-01

    The seeds of Lamb's Quarters (Chenopodium album agg.) were stimulated by low-pressure discharge. The tested seeds were exposed to plasma discharge for different time durations (from 6 minutes to 48 minutes). Germination tests were performed under specified laboratory conditions during seven days in five identical and completely independent experiments. Significant differences between the control and plasma-treated seeds were observed. The treated seeds showed structural changes on the surface of the seat coat. They germinated faster and their sprout accretion on the first day of seed germination was longer. Germination rate for the untreated seeds was 15% while it increased approximately three times (max 55%) for seeds treated by plasma from 12 minutes to 48 minutes.

  18. Effect of Pretreatments on Seed Germination of Prunus mahaleb L

    National Research Council Canada - National Science Library

    Elias PIPINIS; Elias MILIOS; Olga MAVROKORDOPOULOU; Christina GKANATSIOU; Maria ASLANIDOU; Pavlos SMIRIS

    2012-01-01

    Sexual propagation of Prunus mahaleb is difficult due to seed dormancy. To overcome dormancy and maximize germination, various pretreatments have been applied, including stratification (warm and cold), gibberellic acid (GA3...

  19. Autotoxicity of chard and its allelopathic potentiality on germination ...

    African Journals Online (AJOL)

    SERVER

    2008-04-03

    Apr 3, 2008 ... weed management, weeds are still responsible for the ... incidence of resistance to herbicides in weeds (Valverde .... their metabolic changes during germination in response ..... Freedman and Company, San Francisco.

  20. 7 CFR 201.53 - Source of seeds for germination.

    Science.gov (United States)

    2010-01-01

    ... separation of the kind, variety, or type considered pure seed and shall be counted without discrimination as to size or appearance. (b) When only a germination test is required and the pure seed is estimated...

  1. Effects of tallowtree seed coat on seed germination

    Institute of Scientific and Technical Information of China (English)

    LI Shu-xian; GU Hong-biao; MAO Yan; YIN Tong-ming; GAO Han-dong

    2012-01-01

    We measured physiological parameters including water uptake,in-vitro embryo germination ratio,and seed coat structure observed by scanning electron microscopy (SEM) to explore the influence of seed coat on the germination of seeds of tallow tree (Sapium sebiferum (Linn) Roxb.).Tallow tree seeds had good water permeability.We found that germination of cabbage seeds was inhibited when cabbage seeds were soaked in extracted solutions from tallow tree seed coat.Seed coat structure at the side of the radicle appeared to be a barrier to seed germination.We tested methods to break tallow tree seed dormancy.Dormancy of tallow tree seeds was overcome by soaking the seeds in 500 mg·L-1 or 1000 mg·L-1 GA3,followed by 100 days of cold stratification.

  2. Germination at low osmotic potential as a selection criteria for ...

    African Journals Online (AJOL)

    user

    2014-01-08

    Jan 8, 2014 ... the potential to be used as a vigor test in sweet corn. Key words: Osmotic potential, germination, polyethylene glycol, corn, proline ..... J. Food Agric. ... accumulation of genetically modified potatoes (Solanum tuberosum.

  3. The plasma membrane proteome of germinating barley embryos

    DEFF Research Database (Denmark)

    Hynek, Radovan; Svensson, Birte; Jensen, O.N.

    2009-01-01

    was used to reduce soluble protein contamination and enrich for hydrophobic proteins. Sixty-one proteins in 14 SDS-PAGE bands were identified by LC-MS/MS and database searches. The identifications provide new insight into the plasma membrane functions in seed germination.......Cereal seed germination involves a complex coordination between different seed tissues. Plasma membranes must play crucial roles in coordination and execution of germination; however, very little is known about seed plasma membrane proteomes due to limited tissue amounts combined...... with amphiphilicity and low abundance of membrane proteins. A fraction enriched in plasma membranes was prepared from embryos dissected from 18 h germinated barley seeds using aqueous two-phase partitioning. Reversed-phase chromatography on C-4 resin performed in micro-spin columns with stepwise elution by 2-propanol...

  4. In vitro spore germination and gametophytic growth development of ...

    African Journals Online (AJOL)

    SAM

    2014-06-04

    Jun 4, 2014 ... Maximum spore germination rates (84%) were observed in. 70 g/L of sucrose and .... two weeks and gametophyte growth rates (length, width of ..... Smith AR, Pryer KM, Schuettpelz E, Korall P, Schneider H, Wolf PG. (2006).

  5. Seed germination in a southern Australian temperate seagrass

    Science.gov (United States)

    Jarvis, Jessie C.; Sherman, Craig D.H.; York, Paul H.; Smith, Timothy M.

    2017-01-01

    In a series of experiments, seeds from a temperate seagrass species, Zostera nigricaulis collected in Port Phillip Bay, Victoria, Australia were exposed to a range of salinities (20 PSU pulse/no pulse, 25 PSU, 30 PSU, 35 PSU), temperatures (13 °C, 17 °C, 22 °C), burial depths (0 cm, 1 cm, 2 cm) and site specific sediment characteristics (fine, medium, coarse) to quantify their impacts on germination rate and maximum overall germination. In southern Australia the seagrass Z. nigricaulis is a common subtidal species; however, little is known about the factors that affect seed germination which is a potential limiting factor in meadow resilience to natural and anthropogenic disturbances. Overall seed germination was low (large scale rainfall events. As a result, these populations may be particularly susceptible to disturbance with only a seasonally limited capacity for recovery.

  6. Lipoxygenase Activity Accelerates Programmed Spore Germination in Aspergillus fumigatus

    Directory of Open Access Journals (Sweden)

    Gregory J. Fischer

    2017-05-01

    Full Text Available The opportunistic human pathogen Aspergillus fumigatus initiates invasive growth through a programmed germination process that progresses from dormant spore to swollen spore (SS to germling (GL and ultimately invasive hyphal growth. We find a lipoxygenase with considerable homology to human Alox5 and Alox15, LoxB, that impacts the transitions of programmed spore germination. Overexpression of loxB (OE::loxB increases germination with rapid advance to the GL stage. However, deletion of loxB (ΔloxB or its signal peptide only delays progression to the SS stage in the presence of arachidonic acid (AA; no delay is observed in minimal media. This delay is remediated by the addition of the oxygenated AA oxylipin 5-hydroxyeicosatetraenoic acid (5-HETE that is a product of human Alox5. We propose that A. fumigatus acquisition of LoxB (found in few fungi enhances germination rates in polyunsaturated fatty acid-rich environments.

  7. A possible role of chemotaxis in germinal center formation

    CERN Document Server

    Beyer, T; Soff, G; Beyer, Tilo; Meyer-Hermann, Michael; Soff, Gerhard

    2002-01-01

    During the germinal center reaction a characteristic morphology is developed. In the framework of a recently developed space-time-model for the germinal center a mechanism for the formation of dark and light zones has been proposed. The mechanism is based on a diffusing differentiation signal which is secerned by follicular dendritic cells. Here, we investigate a possible influence of recently found chemokines for the germinal center formation in the framework of a single-cell-based stochastic and discrete three-dimensional model. We will also consider alternative possible chemotactic pathways that may play a role for the development of both zones. Our results suggest that the centrocyte motility resulting from a follicular dendritic cell-derived chemokine has to exceed a lower limit to allow the separation of centroblasts and centrocytes. In contrast to light microscopy the dark zone is ring shaped. This suggests that FDC-derived chemoattractants alone cannot explain the typical germinal center morphology.

  8. The role of seed priming in improving seed germination and ...

    African Journals Online (AJOL)

    win7

    2013-11-13

    Nov 13, 2013 ... Salinity is considered as a major abiotic stress affecting germination, seedling growth and crop ... of the metabolic processes involved in the early phases ..... Church Regional Senior Consultant on Environment and Natural.

  9. Histone Acetylation is Involved in Gibberellin-Regulated sodCp Gene Expression in Maize Aleurone Layers.

    Science.gov (United States)

    Hou, Haoli; Wang, Pu; Zhang, Hao; Wen, Huan; Gao, Fei; Ma, Ningjie; Wang, Qing; Li, Lijia

    2015-11-01

    The cereal aleurone layer plays an important role in seed germination, and reactive oxygen species (ROS) in aleurone layers act as crucial signal molecules in this progression. Recent studies have revealed that epigenetic modification is involved in plant development and seed germination. However, little is known about a possible relationship between histone modification and the ROS signaling pathway in cereal aleurone layers during seed germination. Here, we found that the expression of both histone acetyltransferases (HATs) and histone deacetylases (HDACs) was increased gradually during seed germination, accompanied by an increase in global acetylation levels of histones H3 and H4 in maize aleurone layers. The acetylation was found to be promoted by GA(3) and suppressed by ABA. However, when the HDAC inhibitor trichostatin A (TSA) was used, the increased H3K9ac and H4K5ac level correlated with an inhibition of the germination. These results indicated that the overall histone acetylation in the aleurone layers is not required for germination. Similarly these two hormones, GA(3) and ABA, exerted opposed effects on the expression of the ROS-related gene sodCp. Furthermore, chromatin immunoprecipitation experiments showed that the promoter region of the sodCp gene was hyperacetylated during germination, and this acetylation was promoted by GA(3) and inhibited by both ABA and TSA. These results suggested that GA(3)-mediated expression of the sodCp gene in aleurone layers is associated with histone hyperacetylation on the promoter and coding region of this gene, consequently leading to an accumulation of H(2)O(2) which regulated production of α-amylase during seed germination.

  10. Proteomes of the barley aleurone layer: A model system for plant signalling and protein secretion

    DEFF Research Database (Denmark)

    Finnie, Christine; Andersen, Birgit; Shahpiri, Azar

    2011-01-01

    The cereal aleurone layer is of major importance due to its nutritional properties as well as its central role in seed germination and industrial malting. Cereal seed germination involves mobilisation of storage reserves in the starchy endosperm to support seedling growth. In response to gibberel......The cereal aleurone layer is of major importance due to its nutritional properties as well as its central role in seed germination and industrial malting. Cereal seed germination involves mobilisation of storage reserves in the starchy endosperm to support seedling growth. In response...... to gibberellic acid produced by the embryo, the aleurone layer synthesises hydrolases that are secreted to the endosperm for the degradation of storage products. The barley aleurone layer can be separated from the other seed tissues and maintained in culture, allowing the study of the effect of added signalling...... molecules in an isolated system. These properties have led to its use as a model system for the study of plant signalling and germination. More recently, proteome analysis of the aleurone layer has provided new insight into this unique tissue including identification of plasma membrane proteins and targeted...

  11. Seed and Germination Characteristics of 20 Amazonian Liana Species

    Science.gov (United States)

    Roeder, Mareike; Ferraz, Isolde D. K.; Hölscher, Dirk

    2013-01-01

    Lianas are an important component of tropical forests, and may reach their highest densities in disturbed areas. However, information on seed and germination characteristics is scarce. Twenty Amazon liana species were screened for their germination characteristics, including light dependence, tolerance of desiccation and of alternating temperatures; these characteristics are considered important for the germination success in areas with relatively open canopies. Between 31–1,420 seeds per species were available, as 15 species seeds came from one mother plant. We studied seed biometry and conducted germination trials with fresh seeds (12 h light daily, or dark) and desiccated seeds at 25 °C. Germination at alternating temperatures (20/30 °C, 15/35 °C) was analyzed for nine species. Of the 20 species, eight species with the largest seeds had desiccation sensitive seeds; this is the first record for species of four genera and one family, where only desiccation tolerant seeds are otherwise recorded. Light-dependent germination was found in three species (0.01–0.015 g) and is the first record for two; however, results were based on seeds from one plant per species. Alternating temperatures of 15/35 °C decreased final germination of four out of nine species, and response to 20/30 °C cycles varied compared to constant 25 °C. Seed and germination characteristics of the species ranged from pioneer to climax traits indicating that establishment of lianas from seeds may be confined to species specific niches. PMID:27137363

  12. Vermicompost enhances germination of the maritime pine (Pinus pinaster Ait.)

    OpenAIRE

    Lazcano, Cristina; Sampedro, Luis; Zas Arregui, Rafael; Domínguez, Jorge

    2010-01-01

    We investigated the effect of vermicompost on the germination and early development of six different progenies of the maritime pine (Pinus pinaster Ait.). We compared the effects of incorporating solid vermicompost into the potting media to those of vermicompost water extract to asses the extent of not physically-mediated positive effects. The incorporation of vermicompost in the growing media of maritime pine increased germination by 16%, and particularly, addition of vermicom...

  13. Effect of Estrogen and Progeterone on seed germination

    Directory of Open Access Journals (Sweden)

    Nirmala

    Full Text Available Early pregnancy detection in dairy cattle is an integral part of a successful animal husbandry practice. A simple seed germination technique (Punyakoti test comprises observation of differential seed germination response of wheat seeds to diluted fresh urine samples as reflected by significant inhibition of germination percentage in pregnant cow urine when compared to non pregnant cow urine. Hormone metabolites excreted through urine might affect the seed germination in pregnant cow urine. In the present study an attempt was made to test the effect of hormones (in their natural forms at different concentrations of estrogen (17-ß estradiol and progesterone on wheat and green gram germination. Stock solutions of estrogen and progesterone were prepared in alcohol (1mg/ml and serial dilutions made using distilled water to get the concentrations of T1=10, T2=1, T3=0.1 and T4=0.01 μg/ml respectively in treatment groups. About 15 seeds each of wheat and green gram were taken in sterile Petri dishes into which 15ml of each test preparation was poured. The treatments were compared with distilled water and alcohol controls. The study was conducted for a period of five days during which seed germination was observed after 48 hrs and shoot lengths were also measured by the end of study. The average seed germination and shoot length in treatment groups did not vary significantly (P>0.05 when compared with that of control groups. Thus from the present study, it can be concluded that estrogen and progesterone in their natural form will not affect seed germination and shoot length. [Veterinary World 2008; 1(8.000: 241-242

  14. Seed Germination of Some Crocus Species of Western Anatolia

    OpenAIRE

    HASPOLAT, Gülden; ÖZZAMBAK, M. Ercan; ŞIK, Levent

    2013-01-01

    In this study, germination studies were carried out on some Crocus species such as Crocus olivieri ssp. balansae, Crocus chrysanthus, Crocus baytopiorum, Crocus pallasii ssp. pallasii spreading at western Anatolia. Seed viability was determined by using tetrazolium test. Testa, endosperm, embryo bed of seeds were examined at stereo binocular. The pretreatments for germination were; waiting seeds in moist sand at 5oC for 4 weeks, keeping seeds for 24 hours in water and in 200400 mg/l GA3 solut...

  15. Ribosomal ribonucleic acid maturation during bacterial spore germination.

    Science.gov (United States)

    Bleyman, M; Woese, C

    1969-01-01

    All the ribosomal ribonucleic acid made during the early stages of germination of spores of Bacillus subtilis is of the "precursor" type, i.e., that type appearing in the incomplete forms of the ribosome. Shortly before the onset of deoxyribonucleic acid synthesis in germination, this precursor ribonucleic acid changed to the mature ribosomal ribonucleic acid characteristic of the 30S and 50S ribosomal subunits.

  16. Cortex Peptidoglycan Lytic Activity in Germinating Bacillus anthracis Spores▿

    OpenAIRE

    2008-01-01

    Bacterial endospore dormancy and resistance properties depend on the relative dehydration of the spore core, which is maintained by the spore membrane and its surrounding cortex peptidoglycan wall. During spore germination, the cortex peptidoglycan is rapidly hydrolyzed by lytic enzymes packaged into the dormant spore. The peptidoglycan structures in both dormant and germinating Bacillus anthracis Sterne spores were analyzed. The B. anthracis dormant spore peptidoglycan was similar to that fo...

  17. Seed and germination characteristics of wild Onobrychis taxa in Turkey

    OpenAIRE

    AVCI, Süleyman; KAYA, Mehmet Demir

    2013-01-01

    Turkey is of great importance for the biodiversity of genus Onobrychis Adans. and hosts 55 species that are adapted to dry and poor environments. This study was conducted to evaluate 35 Onobrychis taxa in terms of 1000-seed weight, germination percentage, mean germination time, and hard and swollen seeds and to determine the suitability of mechanical scarification for dormancy breaking in species with hard or impermeable seed coats. Seed dormancy was detected in 19 of the investigated species...

  18. The germinal center antibody response in health and disease

    OpenAIRE

    DeFranco, Anthony L.

    2016-01-01

    The germinal center response is the delayed but sustained phase of the antibody response that is responsible for producing high-affinity antibodies of the IgG, IgA and/or IgE isotypes. B cells in the germinal center undergo re-iterative cycles of somatic hypermutation of immunoglobulin gene variable regions, clonal expansion, and Darwinian selection for cells expressing higher-affinity antibody variants. Alternatively, selected B cells can terminally differentiate into long-lived plasma cells...

  19. Seed and Germination Characteristics of 20 Amazonian Liana Species

    Directory of Open Access Journals (Sweden)

    Mareike Roeder

    2013-01-01

    Full Text Available Lianas are an important component of tropical forests, and may reach their highest densities in disturbed areas. However, information on seed and germination characteristics is scarce. Twenty Amazon liana species were screened for their germination characteristics, including light dependence, tolerance of desiccation and of alternating temperatures; these characteristics are considered important for the germination success in areas with relatively open canopies. Between 31–1,420 seeds per species were available, as 15 species seeds came from one mother plant. We studied seed biometry and conducted germination trials with fresh seeds (12 h light daily, or dark and desiccated seeds at 25 °C. Germination at alternating temperatures (20/30 °C, 15/35 °C was analyzed for nine species. Of the 20 species, eight species with the largest seeds had desiccation sensitive seeds; this is the first record for species of four genera and one family, where only desiccation tolerant seeds are otherwise recorded. Light-dependent germination was found in three species (0.01–0.015 g and is the first record for two; however, results were based on seeds from one plant per species. Alternating temperatures of 15/35 °C decreased final germination of four out of nine species, and response to 20/30 °C cycles varied compared to constant 25 °C. Seed and germination characteristics of the species ranged from pioneer to climax traits indicating that establishment of lianas from seeds may be confined to species specific niches.

  20. Enhanced germination and gravitropism of soybean in a hypogeomagnetic field

    Science.gov (United States)

    Mo, Weichuan

    For the future manned space exploration, the duration of the missions would significantly in-crease. Investigating plant growth and development under the space environmental conditions is of essential importance for the food supply projects for the astronauts. Hypogeomagnetic field (HGMF), namely, extremely low magnetic field, is one of the main characters of the space environment. Germination is the first vital step of plant growth and development, which determines the final yield of plants. The effect of HGMF on plant growth, especially early ger-mination, still remains open. In this study, we established a hypogeomagnetic field (HGMF) incubation system, the remnant magnetic field inside no more than 250 nT. Soybean seeds were incubated at 25 in HGMF, and the very beginning of soybean germination, from water ab-sorbance of cotyledon to radicle emergence, was examined within 24 h. Our results showed that the germination ratio and weight ratio of emerged soybean radicles were markedly increased during germination in HGMF. Furthermore, the tropism angle of emerged radicle with gravity in HGMF was statistically smaller than that in GMF when the radicle direction was placed opposite to gravity before germination. These results indicate that the germination and gravit-ropism of soybean is enhanced in a hypogeomagnetic environment, This is a new finding about the early seed germination in such a low environmental magnetic field which is comparable to the magnetic field of Lunar Swirls on the Moon (a few hundred nT), and it might provide new perspectives on the space science researches concerning plant growth and food supply.

  1. Pollen germination in vitro of Mexican Crataegus spp.

    Directory of Open Access Journals (Sweden)

    M. W. Borys

    2014-01-01

    Full Text Available The germination of pollen in vitro of 42 selections of Crataegus belonging to the cultivated group (C. pubescens (H.B.K. Steud. = C. mexicana Moc. et Sessé and wild group (probably C. nelsoni Eggleston was evaluated. The anthers size (length and width of each selection was also determined. Both attributes were determined by using undehisced anthers of flowers of the spring flowering period (dry season. The percent of germinated pollen varied from 82.4 to 94.2%, depending upon the selection; both groups of selections gave similar values of germination. The 45.83% of selections of the wild group gave from 88 to 90% of germinated pollen. The selections of cultivated group have been characterized by a wide range of pollen germination. The anther size - length and width - depended upon the selection. The plants of the cultivated group showed a larger size more frequently than those of the wild group. No correlation was found between pollen germination and anthers dimensions. The results were discussed in relation to productivity of fruits trees of the Mexican representatives included in the germplasm collection.

  2. TIME REDUCTION FOR SURINAM GRASS SEED GERMINATION TEST

    Directory of Open Access Journals (Sweden)

    Camila de Aquino Tomaz

    2015-10-01

    Full Text Available ABSTRACTThe period for the germination test of Surinam grass seeds established by the Rules for Seeds Testing is 28 days, considered too lengthy by producers, venders, and seed analysis laboratories. So, the objective of this research was to evaluate the possibility of reducing the time for the germination test of Surinam grass seeds and to establish a method for dormancy breaking and the ideal temperature. Ten seed lots were submitted to the following treatments to overcome seed dormancy: control; substrate moistening with 0.2% KNO3; and scarification with sulfuric acid (98% 36 N for 15 minutes. After the treatments, the lots were submitted to seed water content, germination and tetrazolium tests. During the germination test, conducted with four replicates of 100 seeds per treatment for 28 days, two conditions of alternating temperatures (20-35 °C and 15-35 °C with 8 hours of light were tested. Attempting to determine the test end date, daily counts of the number of normal seedlings were made and for each lot, treatment, and temperature, a growth curve for the evaluation of germination was adjusted. The segmented regression model parameter estimations were calculated for each treatment. The germination test of Braquiaria decumbensseeds may be evaluated in 12 days after sowing using alternating temperatures of 20-35 °C and without any treatment to overcome dormancy.

  3. Improving Seed Germination and Peanut Yields by Cold Plasma Treatment

    Science.gov (United States)

    Li, Ling; Li, Jiangang; Shen, Minchong; Hou, Jinfeng; Shao, Hanliang; Dong, Yuanhua; Jiang, Jiafeng

    2016-10-01

    This study explored the effects of cold plasma treatment on seed germination, plant growth, and peanut yield. Cold plasma treatment improved germination and seedling growth, and the 120 W treatment produced the best effect. Germination potential and germination rate were markedly raised by 150% and 21%, respectively. Germination was accelerated and the uniformity of emergence improved. The apparent contact angle was decreased by 53%. Seedling shoot and root dry weights increased by 11% and 9%. Leaf area, leaf thickness, leaf nitrogen concentration, chlorophyll contents, and dry weight at the fruiting stage, together with plant height, stem diameter, and root dry weight at the mature stage were all markedly raised by the cold plasma treatment. The cold plasma treatment enhanced yield components, such as branch numbers per plant, pod numbers per plant, and 100 pod weights by 8%, 13%, and 9%, respectively, compared to the control. Furthermore, the yield improved by 10%. These results suggested that cold plasma treatment improved germination, plant growth, and yield, which might be due to the cold plasma increasing the leaf area, nitrogen concentrations, and chlorophyll contents. supported by National Key Technology Research and Development Program of the Ministry of Science and Technology of China (No. 2012BAD05B04), National Natural Science Foundation of China (No. 41201241), “Strategic Priority Research Program” of the Chinese Academy of Sciences (No. XDB15030301) and Jiangsu Province Science and Technology Support Program (No. BE2013452)

  4. YY1 Is Required for Germinal Center B Cell Development.

    Science.gov (United States)

    Banerjee, Anupam; Sindhava, Vishal; Vuyyuru, Raja; Jha, Vibha; Hodewadekar, Suchita; Manser, Tim; Atchison, Michael L

    2016-01-01

    YY1 has been implicated as a master regulator of germinal center B cell development as YY1 binding sites are frequently present in promoters of germinal center-expressed genes. YY1 is known to be important for other stages of B cell development including the pro-B and pre-B cells stages. To determine if YY1 plays a critical role in germinal center development, we evaluated YY1 expression during B cell development, and used a YY1 conditional knock-out approach for deletion of YY1 in germinal center B cells (CRE driven by the immunoglobulin heavy chain γ1 switch region promoter; γ1-CRE). We found that YY1 is most highly expressed in germinal center B cells and is increased 3 fold in splenic B cells activated by treatment with anti-IgM and anti-CD40. In addition, deletion of the yy1 gene by action of γ1-CRE recombinase resulted in significant loss of GC cells in both un-immunized and immunized contexts with corresponding loss of serum IgG1. Our results show a crucial role for YY1 in the germinal center reaction.

  5. Regularization by External Variables

    DEFF Research Database (Denmark)

    Bossolini, Elena; Edwards, R.; Glendinning, P. A.

    2016-01-01

    Regularization was a big topic at the 2016 CRM Intensive Research Program on Advances in Nonsmooth Dynamics. There are many open questions concerning well known kinds of regularization (e.g., by smoothing or hysteresis). Here, we propose a framework for an alternative and important kind of regula...... of regularization, by external variables that shadow either the state or the switch of the original system. The shadow systems are derived from and inspired by various applications in electronic control, predator-prey preference, time delay, and genetic regulation....

  6. Carbon nanofibers suppress fungal inhibition of seed germination of maize (Zea mays) and barley (Hordeum vulgare L.) crop

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Anjali, E-mail: joshianjali1982@gmail.com; Sharma, Arti [Centre For Nanoscience and Nanotechnology, Panjab University, Chandigarh (India); Nayyar, Harsh [Department of Botany, Panjab University, Chandigarh (India); Verma, Gaurav [Dr. SS Bhatnagar University Institute of Chemical Engineering and Technology, Panjab University, Chandigarh (India); Dharamvir, Keya [Department of Physics, Panjab University, Chandigarh (India)

    2015-08-28

    Carbon nanofibers (CNFs) are one of allotropes of carbon, consists of graphene layers arrangement in the form of stacked cones or like a cup diameter in nanometer and several millimeters in length. Their extraordinary mechanical, chemical and electronic properties are due to their small size. CNFs have been successfully applied in field of medicine in variety of diagnostic methods. They proven to be an excellent system for drug delivery, tissue regeneration, biosensor etc. This research focuses the applications of CNFs in all fields of Agriculture. In the we treated some fungal disease seed of maize and barley using functionalised CNFs. We find that the tested seeds grow just as well as the healthy seeds whereas the untreated fungal disease seeds, by themselves show very poor germination and seedling growth. This simple experiment shows the extraordinary ability of Carbon nanofibers in carrying effectively inside the germinated seeds.

  7. Carbon nanofibers suppress fungal inhibition of seed germination of maize (Zea mays) and barley (Hordeum vulgare L.) crop

    Science.gov (United States)

    Joshi, Anjali; Sharma, Arti; Nayyar, Harsh; Verma, Gaurav; Dharamvir, Keya

    2015-08-01

    Carbon nanofibers (CNFs) are one of allotropes of carbon, consists of graphene layers arrangement in the form of stacked cones or like a cup diameter in nanometer and several millimeters in length. Their extraordinary mechanical, chemical and electronic properties are due to their small size. CNFs have been successfully applied in field of medicine in variety of diagnostic methods. They proven to be an excellent system for drug delivery, tissue regeneration, biosensor etc. This research focuses the applications of CNFs in all fields of Agriculture. In the we treated some fungal disease seed of maize and barley using functionalised CNFs. We find that the tested seeds grow just as well as the healthy seeds whereas the untreated fungal disease seeds, by themselves show very poor germination and seedling growth. This simple experiment shows the extraordinary ability of Carbon nanofibers in carrying effectively inside the germinated seeds.

  8. Two cytosolic glutamine synthetase isoforms play specific roles for seed germination and seed yield structure in Arabidopsis.

    Science.gov (United States)

    Guan, M; Møller, I S; Schjoerring, J K

    2015-01-01

    Nitrogen (N) remobilization from reserves to sinks is essential for seedling establishment and seed production. Cytosolic glutamine synthetase (GS1) is up-regulated during both seed germination and seed filling in plants. However, the specific roles of the individual GS1 isogenes with respect to N remobilization, early seedling vigour, and final seed productivity are not known. In this study, impairment of seed germination and seedling establishment is demonstrated in the single knockout mutant gln1;2, and the double knockout mutant gln1;1:gln1;2. The negative effect of Gln1;2 deficiency was associated with reduced N remobilization from the cotyledons and could be fully alleviated by exogenous N supply. Following reproductive growth, both the single and double Gln1;2-knockout mutants showed decreased seed yield due to fewer siliques, less seeds per silique, and lower dry weight per seed. The gln1;1 single mutant had normal seed yield structure but primary root development during seed germination was reduced in the presence of external N. Gln1;2 promoter-green fluorescent protein constructs showed that Gln1;2 localizes to the vascular cells of roots, petals, and stamens. It is concluded that Gln1;2 plays an important role in N remobilization for both seedling establishment and seed production in Arabidopsis.

  9. Effect of zinc sulfate fortification in germinated brown rice on seed zinc concentration, bioavailability, and seed germination.

    Science.gov (United States)

    Wei, Yanyan; Shohag, M J I; Wang, Yuyan; Lu, Lingli; Wu, Chunyong; Yang, Xiaoe

    2012-02-22

    Rice is the staple food for more than half of the world's population and, hence, the main source of a vital micronutrient, zinc (Zn). Unfortunately, the bioavailability of Zn from rice is very low not only due to low content but also due to the presence of some antinutrients such as phytic acid. We investigated the effect of germination and Zn fortification treatment on Zn bioavailability of brown rice from three widely grown cultivars using the Caco-2 cell model to find a suitable fortification level for producing germinated brown rice. The results of this study showed that Zn content in brown rice increased significantly (p 0.05) on germination percentage of rice was observed when the Zn supply was lower than 150 mg/L. Zn fortification during the germination process has a significant impact on the Zn content and finally Zn bioavailability. These findings may result from the lower molar ratio of phytic acid to Zn and higher Zn content in Zn fortified germinated brown rice, leading to more bioavailable Zn. Likewise, a significant difference (p world population, we recommend germinated brown rice fortified with 100 mg/L ZnSO(4) as a suitable concentration to use in the germination process, which contains high Zn concentration and Zn bioavailability. In the current study, the cultivar Bing91185 fortified with Zn through the germination process contained a high amount as well as bioavailable Zn, which was identified as the most promising cultivar for further evaluation to determine its efficiency as an improved source of Zn for target populations.

  10. EFFECTS OF DIFFERENT PRE-TREATMENTS AND GERMINATION MEDIA ON SEED GERMINATION AND SEEDLING GROWTH OF Parkia timoriana (DC. Merr

    Directory of Open Access Journals (Sweden)

    Uttam Thangjam

    2017-02-01

    Full Text Available Parkia timoriana (DC. Merr. is one of the lesser known multipurpose leguminous tree species found in North East India. Like many other legumes this species too have hard coated seeds which prevent seed germination and thus there is a need to investigate the most appropriate method to break its dormancy. Six pre treatments (tap water, gibberellic acid (GA3 @ 500 ppm, stratification, sulphuric acid @ 98%, boiling water and nicking and two media (top of paper (TOP and sand were use to evaluate seed germination traits and initial growth parameters of the seedling of this tree species. Along with these pre treatments, seeds sown in TOP media and tap water gave maximum seed germination (72% and it was followed by seeds exposed to GA₃ for 24 hours (64% while the least seed germination was reported in seeds treated with sulphuric acid (H2SO4 for 5 minutes. Least germination time (Mean Germination Time was reported from the seeds treated with H2SO4 for 1 minute while maximum was reported from the boiling water treatments. Under sand medium, highest germination was reported in control (66.67 % and it was followed by boiling water treatment (58.33% and minimum (16.67% in seeds treated with H2SO4 for 5 minute. Seed treated with H2SO4 for 5 minutes took minimum germination time too. Interestingly, irrespective to the media, all the seedling growth parameters showed maximum response towards hormonal (GA3 treatment and minimum towards H2SO4 treatment. Significant correlations were found between all the seedling growth parameters except for collar diameter and root-shoot ratio

  11. Aminopeptidase activity from germinated jojoba cotyledons.

    Science.gov (United States)

    Johnson, R; Storey, R

    1985-11-01

    One major and two minor aminopeptidase activities from germinated jojoba (Simmondsia chinensis) cotyledon extracts were separated by ammonium sulfate precipitation and chromatofocusing. None of the activities were inhibited by 1,10 phenanthroline.The major aminopeptidase, purified 260-fold, showed a pH optimum of 6.9 with leucine-p-nitroanilide as substrate, a molecular weight estimated at 14,200 by electrophoretic analysis, and an isoelectric point of 4.5 according to the chromatofocusing pattern. Activity was inhibited by p-chloromercuribenzoate, slightly stimulated by 1,10 phenanthroline and 2-mercaptoethanol, and not influenced by Mg(2+) or diethyl pyrocarbonate. Inhibition by p-chloromercuribenzoate was prevented by the presence of cysteine in the assay. Leucine-p-nitroanilide and leucine-beta-naphthylamide were the most rapidly hydrolyzed of 11 carboxy-terminal end blocked synthetic substrates tested. No activity on endopeptidase or carboxypeptidase specific substrates was detected. The major aminopeptidase showed activity on a saline soluble, jojoba seed protein preparation and we suggest a possible physiological role for the enzyme in the concerted degradation of globulin reserve proteins during cotyledon senescence.

  12. Maternal Germinal Trisomy 21 in Down Syndrome

    Directory of Open Access Journals (Sweden)

    Maj A. Hultén

    2014-01-01

    Full Text Available It has now been over 50 years since it was discovered that Down syndrome is caused by an extra chromosome 21, i.e., trisomy 21. In the interim, it has become clear that in the majority of cases, the extra chromosome is inherited from the mother, and there is, in this respect, a strong maternal age effect. Numerous investigations have been devoted to clarifying the underlying mechanism, most recently suggesting that this situation is exceedingly complex, involving both biological and environmental factors. On the other hand, it has also been proposed that germinal trisomy 21 mosaicism, arising during the very early stages of maternal oogenesis with accumulation of trisomy 21 germ cells during subsequent development, may be the main predisposing factor. We present data here on the incidence of trisomy 21 mosaicism in a cohort of normal fetal ovarian samples, indicating that an accumulation of trisomy 21 germ cells does indeed take place during fetal oogenesis, i.e., from the first to the second trimester of pregnancy. We presume that this accumulation of trisomy 21 (T21 cells is caused by their delay in maturation and lagging behind the normal cells. We further presume that this trend continues during the third trimester of pregnancy and postnatally, up until ovulation, thereby explaining the maternal age effect in Down syndrome.

  13. La organización germinal

    Directory of Open Access Journals (Sweden)

    Xavier Soca Filella

    2013-08-01

    Full Text Available Las vicisitudes de estos últimos años en las economías occidentales, y sobre todo en las del arco mediterráneo, han sumido las empresas en un profundo callejón sin salida, dónde tras efectuar reducciones drásticas en sus estructuras ahora ven mermadas sus posibilidades de crecimiento. Surge el interrogante de qué tipo de crecimiento perseguimos y qué organización precisamos para conseguirlo. Vislumbramos a partir de lo acaecido en los últimos dos lustros que las organizaciones preferirán moverse dentro de unos patrones de crecimientos sostenibles, en lugar de las alocadas carreras de inicios de siglo. Este crecimiento sostenible comportará decidir que formas de organización permitirán gestionar mejor este crecimiento. Dentro del abanico de las posibilidades, planteo un tipo de organización en constante cambio que facilite la adaptación a los diversos tipos de mercados que puedan ir surgiendo en el futuro: LA ORGANIZACIÓN GERMINAL.

  14. Stabilization of unstable pelvic fractures with a novel internal-external fixator

    Institute of Scientific and Technical Information of China (English)

    JIANG Zan-li; Gary Chen

    2011-01-01

    An internal-external fixator for stabilization in three cases with unstable pelvic fractures were reported.Compared with external fixation,the internal-external fixator,which is placed in the subcutaneous layer,decreased the risk of pin-track infection,pin site pain,and bowel obstruction; meanwhile,it had the advantage of external fixation:it was easy to apply,controlled damage,and resulted in minimal injury.

  15. Temperature in the seeds germination of pitaya genotypes

    Directory of Open Access Journals (Sweden)

    Alessandro Borini Lone

    2014-09-01

    Full Text Available The optimum temperature for germination of cacti vary with the species. With this work, we aimed to evaluate the seeds germination of pitaya genotypes under different temperatures. The used genotypes were: Hylocereus undatus (PB, H. polyrhizus (PV, Selenicereus megalanthus (PA, H. undatus x H. costaricensis (PH1 and H. costaricensis x H. undatus (PH2. For each genotype we used four replicates of 50 seeds, in a completely randomized design. The sowing was carried out on blotter paper in boxes type Gerbox ®, maintained at temperatures of 15, 20, 25, 30 and 35 oC constant and 15-25, 20-30 and 25-35 oC alternating with photoperiod 12 hours. The test lasted 30 days which were appraised the germination percentage, the germination speed index and the average time of germination. For seeds germination of PB, the result obtained in the temperature of 25 oC didn’t differ of the obtained to 30 and 20-30 oC, however it was superior to the others temperatures. In PV, the result at 25 oC didn’t differ of the obtained to 20 and 30 oC, being superior to the results of the others temperatures. For PA, the best result was obtained to 25 oC. In PH1, the temperatures of 25, 30 and 20-30 oC presented superiors results to the others. For PH2, the result obtained in 15-25oC didn’t differ of the obtained at 25 oC, however it was superior to the others temperatures. The constants temperatures of 25 and 30 °C and alternating 20-30 °C are suitable for germination of H. undatus and for the hybrid H. undatus x H. costaricensis. For H. polyrhizus, constant temperatures of 20, 25 to 30 °C are suitable for seed germination. The constant temperature of 25 °C is the most suitable for the germination of S. megalanthus. For the hybrid H. costaricensis x H. undatus, constant temperature of 25 °C and alternating 15-25°C are suitable for seed germination.

  16. Multiple layers of B cell memory with different effector functions.

    Science.gov (United States)

    Dogan, Ismail; Bertocci, Barbara; Vilmont, Valérie; Delbos, Frédéric; Mégret, Jérome; Storck, Sébastien; Reynaud, Claude-Agnès; Weill, Jean-Claude

    2009-12-01

    Memory B cells are at the center of longstanding controversies regarding the presence of antigen for their survival and their re-engagement in germinal centers after secondary challenge. Using a new mouse model of memory B cell labeling dependent on the cytidine deaminase AID, we show that after immunization with a particulate antigen, B cell memory appeared in several subsets, comprising clusters of immunoglobulin M-positive (IgM(+)) and IgG1(+) B cells in germinal center-like structures that persisted up to 8 months after immunization, as well as IgM(+) and IgG1(+) B cells with a memory phenotype outside of B cell follicles. After challenge, the IgG subset differentiated into plasmocytes, whereas the IgM subset reinitiated a germinal center reaction. This model, in which B cell memory appears in several layers with different functions, reconciles previous conflicting propositions.

  17. External Measures of Cognition

    Directory of Open Access Journals (Sweden)

    Osvaldo eCairo

    2011-10-01

    Full Text Available The human brain is undoubtedly the most impressive, complex and intricate organ that has evolved over time. It is also probably the least understood, and for that reason, the one that is currently attracting the most attention. In fact, the number of comparative analyses that focus on the evolution of brain size in Homo sapiens and other species has increased dramatically in recent years. In neuroscience, no other issue has generated so much interest and been the topic of so many heated debates as the difference in brain size between socially defined population groups, both its connotations and implications. For over a century, external measures of cognition have been related to intelligence. However, it is still unclear whether these measures actually correspond to cognitive abilities. In summary, this paper must be reviewed with this premise in mind.

  18. Seed priming to alleviate salinity stress in germinating seeds.

    Science.gov (United States)

    Ibrahim, Ehab A

    2016-03-15

    Salinity is one of the major abiotic stresses that affect crop production in arid and semiarid areas. Seed germination and seedling growth are the stages most sensitive to salinity. Salt stress causes adverse physiological and biochemical changes in germinating seeds. It can affect the seed germination and stand establishment through osmotic stress, ion-specific effects and oxidative stress. The salinity delays or prevents the seed germination through various factors, such as a reduction in water availability, changes in the mobilization of stored reserves and affecting the structural organization of proteins. Various techniques can improve emergence and stand establishment under salt conditions. One of the most frequently utilized is seed priming. The process of seed priming involves prior exposure to an abiotic stress, making a seed more resistant to future exposure. Seed priming stimulates the pre-germination metabolic processes and makes the seed ready for radicle protrusion. It increases the antioxidant system activity and the repair of membranes. These changes promote seed vigor during germination and emergence under salinity stress. The aim of this paper is to review the recent literature on the response of plants to seed priming under salinity stress. The mechanism of the effect of salinity on seed germination is discussed and the seed priming process is summarized. Physiological, biochemical and molecular changes induced by priming that lead to seed enhancement are covered. Plants' responses to some priming agents under salinity stress are reported based on the best available data. For a great number of crops, little information exists and further research is needed.

  19. Layer-by-layer magnetometry of polarizing supermirrors

    CERN Document Server

    Ruecker, U; Toperverg, B; Brueckel, T; Ott, F

    2002-01-01

    We investigate the remagnetization behaviour of remanent polarizing supermirrors by polarized neutron reflectometry. Such a mirror can be remagnetized in a magnetic field of 30 mT. It is shown, that at lower fields, the mirror is not completely remagnetized, but the magnetization of the thinner layers can be flipped more easily than the magnetization of the thicker layers. With polarized neutron reflectometry, we are able to find out exactly how many layers are magnetized parallel and how many are magnetized antiparallel to the external field. Furthermore, information about structural and magnetic imperfections (roughness, domain formation) is available. (orig.)

  20. Destruction of the germinal disc region of an immature preovulatory chicken follicle induces atresia and apoptosis.

    Science.gov (United States)

    Yao, H H; Volentine, K K; Bahr, J M

    1998-09-01

    The germinal disc region (GDR), which contains the germinal disc and overlying granulosa cells, is essential for completion of maturation of the preovulatory chicken follicle. The current study was conducted to test the hypothesis that destruction of the GDR (GDRX) of an immature preovulatory chicken follicle blocks ovulation, induces apoptosis, and causes atresia. The GDR of immature preovulatory follicles (F2) were destroyed by freezing with dry ice (3 mm in diameter) 48-50 h before ovulation. As a control for the effect of freezing, a nonGDR portion (a portion of the follicular wall opposite to the GDR relative to the follicular stalk) of other F2 follicles were destroyed (nonGDRX). Treatment of F2 follicles by GDRX caused atresia and blocked ovulation of all treated follicles (6 of 6), whereas none of the nonGDRX follicles (0 of 5) underwent atresia. Treatment of follicles by GDRX induced apoptotic DNA fragmentation (laddering) in theca and granulosa layers obtained from the frozen area and in the theca layer obtained from the follicular wall distal to the frozen area. In contrast, apoptosis was only present in theca and granulosa layers in the frozen area of the nonGDRX follicle. Furthermore, the in situ DNA end-labeling technique demonstrated that in the GDRX follicle 24 h after treatment, cells in the theca interna, endothelial cells in blood vessels of the theca externa, and a few granulosa cells underwent apoptosis. These results indicate that destruction of the GDR of an immature preovulatory follicle causes atresia and apoptosis and blocks ovulation. These novel findings suggest that the GDR maintains development of the chicken preovulatory follicle by producing one or more survival factors. Without the GDR, chicken follicles cannot develop further and they eventually die.

  1. The type of seeder cells determines the efficiency of germinal center reactions

    CERN Document Server

    Meyer-Hermann, M; Meyer-Hermann, Michael; Beyer, Tilo

    2002-01-01

    We discuss the origin of two classes of germinal centers that have been observed during humoral immune responses: Some germinal centers develop very well and give rise to a large number of high affinity antibody producing plasma cells. Other germinal center reaction are very weak and the output production is practically absent. We propose an explanation for this nearly all-or-none behavior of germinal center reactions: The affinity of the seeder B-cells to the antigen is the critical parameter that determines the fate of the germinal center reaction. This hypothesis is verified in the framework of a space-time simulation of germinal center reactions.

  2. Effect of HCA age on Germination Characteristics of Soil Seed Bank in Ningxia Desert Steppe%不同封育年限对宁夏荒漠草原土壤种子库萌发特征的影响研究

    Institute of Scientific and Technical Information of China (English)

    刘华; 王占军

    2016-01-01

    采用种子萌发法对不同封育时间(封育1年、封育3年、封育6年)样地的土壤种子库萌发特征进行了研究。结果表明:在0~5 cm土层不同封育年限土壤种子库的萌发基本趋势为,在第3天开始萌发,先增大后减小,在萌发的3~13 d为快速萌发期,萌发的最大值出现在第11天至第13天,在萌发的30 d后萌发的种子数较少;与0~5 cm土层相比,6~10 cm土层土壤种子库萌发较少,萌发曲线波动较小。说明土壤中可萌发种子数量不是随着封育年限的增加而增加。%The germination characteristics of soil seed bank were studied in 1 year, 3 years and 6 years of HCA with germi-nation method. The result showed that in the 3rd day, 0~5 cm soil layer HCA seeds began to germinate, increase and then decrease; from the 3rd~13th day, the germination speed became faster; the germination maximum was in the 11th ~13th day; after 30 days the germination seeds became fewer. Compared with the 0~5 cm soil layer, the 6~10 cm layer germi-nation seeds were fewer and its germination curve changed gently. The result showed that germinating seeds in the soil and HCA ages were not proportional.

  3. Defects in germinal center selection in SLE

    Directory of Open Access Journals (Sweden)

    Megan eWoods

    2015-08-01

    Full Text Available Germinal centers (GCs are the primary site at which clonal expansion and affinity maturation of B cells occurs. B cells encounter antigen and receive T cell help in the GC light zone (LZ and then migrate to the dark zone where they proliferate and undergo somatic mutation before cycling back to the LZ for further rounds of selection. Tolerance to autoantigens is frequently lost de novo as GC B cells undergo class switching and somatic mutation. This loss of tolerance is regulated by a variety of mechanisms including cell death, failure to compete for T cell help and failure to differentiate into effector cells. Systemic Lupus Erythematosus (SLE is characterized by loss of tolerance to nucleic acid antigens. While defects in tolerance occur in the naïve repertoire of SLE patients, pathogenic autoantibodies also arise in the GC as a result of failure to exclude autoreactive B cells from the GC and by somatic mutation from non-autoreactive precursors. Several B cell defects contribute to the loss of GC tolerance in SLE, including polymorphisms of genes that regulate BCR signaling, excess TLR7 signaling, defects in FcRIIB expression or defects of B cell apoptosis. Extrinsic soluble factors such as Type1 IFN or an imbalance between the number of TFH cells and regulatory T cells in the GC can also alter B cell negative selection. Finally, defects in macrophage clearance of apoptotic debris within the GC result in BCR mediated internalization of nucleic acid containing material and stimulation of autoantibody production by endosomal TLR driven mechanisms.

  4. INFLUENCE OF pH AND TEMPERATURE ON GERMINATION ENERGY, GERMINATION, ROOT AND SEEDLINGS HYPOCOTIL LENGTH OF VARIOUS ALFALFA CULTIVARS (Medicago sativa L.

    Directory of Open Access Journals (Sweden)

    Gordana Bukvić

    2008-07-01

    Full Text Available The traits of germination energy, seed germination, as well as root and hypocotyls length of domestic alfalfa cultivars (Slavonka, Stela, Vuka were investigated in a climate chamber. The experiment was set up at two pH levels of water solution (4.00 and 6.00 and temperature levels of 10°C and 20°C using rolled filter paper method. Significant difference between cultivars (p=0.01, p=0.05 was determined for germination energy, seed germination and hypocotyls length. Cultivar Slavonka had the highest average values for germination energy and seed germination, and the lowest for hypocotyls length. Cultivar Vuka had the lowest germination energy (but with the same germination as Stela and the longest hypocotyls. Seed germination as well as root and hypocotyl length significantly depended (p=0.01 on pH of water solution. The higher average values of all traits were found at pH 4.00, except for germination energy. Temperature also significantly affected on all investigated traits (p=0.01, whilst the higher values were attained at higher temperature. Interactions cultivar x pH and cultivar x temperature were significant (p=0.01 for all traits, while pH x temperature interaction was not significant only for seed germination.

  5. Morphological characterization of fruits, diaspores and germination of Miconia ligustroides (DC. Naundim (Melastomataceae - doi: 10.4025/actascibiolsci.v35i1.12648

    Directory of Open Access Journals (Sweden)

    Mariana Aline Silva Artur

    2012-12-01

    Full Text Available Miconia ligustroides (DC. Naudim, popularly known as “vassoura-preta” or “jacatirão-do-brejo” is widely distributed in Brazil. It is a recommended species for restoration of riparian areas and its fruits are attractive to wildlife. However, little is known about the morphology of its fruits and diaspores. Such morphological characterization studies are important for species identification, corroborating future studies of phenology and germination. Therefore, the fruits, diaspores and germination of M. ligustroides were morphologically characterized by observations through naked eye, stereoscopic microscopy and scanning electron microscopy. Analyses of chemical composition of seeds were also performed. The fruits are spherical and uniform within the analyzed sample, having a large number of tiny obtriangular yellowish-brown diaspores. The diaspores are considered ananfitropos, and have crystals in their external envelope. Concerning chemical composition, they are proteins. Germination is of phanerocotylar type and starts at 12 Days After Sowing (DAS; at 17 DAS each diaspore may produce up to three seedlings. The morphological characterization performed in this work was efficient to describe the fruits, seeds and germination of this species, thus providing the basis for future studies.  

  6. Windows of opportunity for germination of riparian species after restoring water level fluctuations: a field experiment with controlled seed banks

    NARCIS (Netherlands)

    Sarneel, J.M.; Janssen, R.H.; Rip, W.J.; Bender, I.; Bakker, E.S.

    2014-01-01

    Restoration activities aiming at increasing vegetation diversity often try to stimulate both dispersal and germination. In wetlands, dispersal and germination are coupled as water and water level fluctuations (WLF) simultaneously influence seed transport and germination conditions (soil moisture). W

  7. Windows of opportunity for germination of riparian species after restoring water level fluctuations : a field experiment with controlled seed banks

    NARCIS (Netherlands)

    Sarneel, Judith M.; Janssen, Roel H.; Rip, Winnie J.; Bender, Irene M. A.; Bakker, Elisabeth S.

    2014-01-01

    1. Restoration activities aiming at increasing vegetation diversity often try to stimulate both dispersal and germination. In wetlands, dispersal and germination are coupled as water and water level fluctuations (WLF) simultaneously influence seed transport and germination conditions (soil moisture)

  8. Germinative potential of encrusted seed of tropical forage species

    Directory of Open Access Journals (Sweden)

    José Rafael de Souza

    Full Text Available ABSTRACT: Brazil is the largest producer, consumer and exporter of seeds of forage species, thus the adoption of new technologies for expansion and maintenance of this market is of great importance. The aim of this work was to evaluate encrustation effect on germination potential in seeds of Brachiaria sp. species. The experiment was carried out in Biofabrica laboratory from June to August 2014, in Universidade Estadual do Sudoeste da Bahia, Vitória da Conquista-BA. The experimental design was completely randomized, in a factorial scheme 6x2, with two treatments (with and without coating and four replications. For germination quality of seeds were evaluated germination and vigor (emergence, emergence speed index, total length of seedling, shoot and root. The encrustation affected positively the germination of seeds in all species tested and encrustation did not affect the total length, shoot and root of the seedlings. Coating after chemical scarification is an alternative to improve germination of the seeds of tropical forage species.

  9. Effects of acidity on tree pollen germination and tube growth

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, J.S.; Van Rye, D.M.; Lassoie, J.P.

    1985-01-01

    Several studies have indicated that pollen germination and tube growth are adversely affected by air pollutants. Pollutants may inhibit the function of pollen by reducing the number of pollen grains which germinate, by reducing the maximum length to which the pollen tubes grow, or by interfering with the formation of the generative cell. The paper reports on studies that are attempting to determine the effects acid rain may have on these crucial stages in the life histories of northeastern tree species. The first stage of this work assessed the effects of acidity in the growth medium on in vitro pollen germination for four deciduous forest species common to central New York State, Betula lutea (yellow birch), B. lenta (black birch), Acer saccharum (sugar maple), and Cornus florida (flowering dogwood). Measurements were taken at the end of the growth period to determine the percentage of grains which had germinated, and to estimate the average tube length. To determine the effects of pollen on the growth medium, the pH of the germination drop was measured at the end of the growth period.

  10. GERMINATION OF GRASSES DUE TO INOCULATION DIAZOTROPHIC BACTERIA

    Directory of Open Access Journals (Sweden)

    C. D. A. Moreira

    2014-07-01

    Full Text Available The germination of forage grasses suffers from numbness and a natural tendency to low quality. The use of microorganisms inoculated in seeds with the purpose of increasing and meet the demand of some nutrient has been shown to be efficient, but the role of the microorganism in germination and rate of force is still unknown. Therefore the goal as study was to evaluate the germination rate of seeds of three cultivars of Brachiaria brizantha CV. Marandu, b., b. brizantha CV. Xaraés and b. humidícola cv Tupi and a cultivar of millet, P. hybrid cv Massai depending on the bacterium Azospirillum brasilense diazotrofic inoculation (nitrogen-fixing. Germination test was used in seed dispersal to assess the effect of first count (VPC in the treatments with and without inoculation. It was done also conducted further tests of electrical conductivity, weight of thousand seeds and water content. The delineation used was randomized entirely (DIC and the statistical analysis carried out through the analysis of variance and comparison of means using the Tukey test, the 5% probability. Massai grass seeds have the highest rate of force of first count in both treatments. Inoculation of bacterium Azospirillum brasilense did not affect the values of force of first count on seeds of the cultivars Marandu, Xaraés, Tupi and Massai. The seeds of the massai have higher germination speed relative the other cultivars evaluated when inoculated.

  11. The Determination of Different Germination Applications on Some Sage Species

    Directory of Open Access Journals (Sweden)

    İmge İhsane Özcan

    2014-05-01

    Full Text Available Sage, which belongs to Labiatae family and contains essential oils, is a typical Mediterranean plant. Being an important and one of the biggest species of this family, sage is said to be named being inspired by the word "Salveo" which means “saver” or “healer” in Latin. Salvia genus is represented by about 900 species on earth. There are 97 natural species of this genus in Turkey’s flora. There is dormancy in seeds of Salvia genus and having mucilage-like seed-coats is an inhibiting factor for germination. Seed germination studies of these species are of great importance in determining production strategies. This research is carried out at 25/15°C, 12 hours in light and 12 hours in dark environment to determine the effects of various germination applications (ethylene, gibberellin, PEG 8000, salicylic acid and seaweed and pre-treatments (pre-drying, pre-cooling and untreated in four species (S. fruticosa, S. officinalis, S. pomifera, S. tomentosa. These trials were conducted at the Department of Field Crops Laboratory of Adnan Menderes University according to completely randomized design with three factors with three replications. Important differences were observed about the germination rate and germination power among the species.

  12. Evaluation of Oxygen Deficit Stress on Germination Indicators and Seedling

    Directory of Open Access Journals (Sweden)

    F Hoseini

    2012-06-01

    Full Text Available To investigate the relationship oxygen deficit stress on germination indicators and seedling growth of five wheat cultivars in laboratory condition, an experiment with Randomized Complete Block design in factorial arrangement with three replications was conducted in 2008. The treatments consisted of five wheat cultivars (Chamran, Flat, Roshan, Stare and Shole as A factor, and two oxygen level (normal seed and seed under oxygen deficit stress conditions as B factor in each of these figures was done. Results showed that oxygen deficit stress caused to decrease for various cultivars germination percentage, germination rate, allometric coefficient, seed vigor index and other germination indicators. Therefore, this test as a suitable method for determining the quality of various seed lot can be used in the water logging condition. In addition, among different cultivars characterized that Roshan cultivar was more resistant to oxygen deficit stress than Chamran, Flat and Star cultivars. Although Chamran cultivar is common cultivar in Khouzestan, but of look most germination indicators arranged as weak seed class. The highest correlation coefficients among the tested cultivars have been related to seed vigor with seedling length and dry weight of radicle with seedling with 0.92 and 0.90, respectively.

  13. Temperature Dependent Seed Germination of Dalbergia nigra Allem (Leguminosae

    Directory of Open Access Journals (Sweden)

    Fernanda G. A. Ferraz-Grande

    2001-12-01

    Full Text Available The germination of endangered species Dalbergia nigra was studied and 30.5° C was found as optimum temperature, although the species presented a broad temperature range where germination occurs and light had no effect. The analysis of kinetics of seed germination confirmed the asynchronized germination below and above the optimum temperature. The light insensitive seed and germination also at high temperatures indicated that D. nigra could occur both in understories and gaps where the mean temperature was high.A germinação de sementes de Dalbergia nigra Allem, comumente conhecida como jacarandá-da-Bahia, caviúna, jacarandá, uma espécie em extinção, foi estudada e determinamos a temperatura ótima de 30,5° C. A espécie apresenta uma ampla faixa de temperatura onde a germinação ocorre e a luz branca não influenciou o processo. A análise da cinética da germinação de sementes confirma a germinação não sincronizada acima e abaixo da temperatura ótima de germinação. A semente insensível à luz e a germinação também em altas temperaturas indicam que D. nigra pode ocorrer tanto na sombra da vegetação bem como em clareiras.

  14. Studies concerning the germination of hop seeds (Humulus lupulus L.

    Directory of Open Access Journals (Sweden)

    Tiberiu SUCIU

    1977-08-01

    Full Text Available Dans les conditions normales les semences de houblon germent avec un faible pourcentage a peine 3-5%. Sur le plan mondial, certaines etudes ont ete faites afin de determiner les causes occasionnant cette faible germination. Malgre tout, les resultants obtenus pratiquement ne s'averent pas encourangeants (2, 3, 4. Concernant les semenes entieres, la germination d'une facon speciale interesse l'anveloppe seminale impermeable a l'eau et a l'oxygene. La temperature dans les differents phases de germination joue aussi un role tres important (1, 2, 5,6. Parlant toujours des semences de houblon, on considere que la germination est inhibee par des substances ameres et des resins continues dans le pericarpe enpechant ainsi, la penetration de l'eau et de l'oxygene jusqu'a l'embryon (2, 3. Ayant aborde ce theme dans un sens complexe et a l'egard de tout ce qui precede, l'amelioration de la germination, des semences obtenuus par hybridation, devient une necessite.

  15. The germinal center antibody response in health and disease.

    Science.gov (United States)

    DeFranco, Anthony L

    2016-01-01

    The germinal center response is the delayed but sustained phase of the antibody response that is responsible for producing high-affinity antibodies of the IgG, IgA and/or IgE isotypes. B cells in the germinal center undergo re-iterative cycles of somatic hypermutation of immunoglobulin gene variable regions, clonal expansion, and Darwinian selection for cells expressing higher-affinity antibody variants. Alternatively, selected B cells can terminally differentiate into long-lived plasma cells or into a broad diversity of mutated memory B cells; the former secrete the improved antibodies to fight an infection and to provide continuing protection from re-infection, whereas the latter may jumpstart immune responses to subsequent infections with related but distinct infecting agents. Our understanding of the molecules involved in the germinal center reaction has been informed by studies of human immunodeficiency patients with selective defects in the production of antibodies. Recent studies have begun to reveal how innate immune recognition via Toll-like receptors can enhance the magnitude and selective properties of the germinal center, leading to more effective control of infection by a subset of viruses. Just as early insights into the nature of the germinal center found application in the development of the highly successful conjugate vaccines, more recent insights may find application in the current efforts to develop new generations of vaccines, including vaccines that can induce broadly protective neutralizing antibodies against influenza virus or HIV-1.

  16. Seed dispersal pattern and germination test of Rhodiola sachalinensis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The survey of seed dispersal of Rhodiola sachalinensis was carried out in Changbai Mountain in 1997. It was discovered that the dispersal of seed is not equal in all directions, but concentrates in the East and North to the cluster. Rh. sachalinensis seeds for germination test were collected from Changbai Mountains area (Antu County, Jilin Province) and Dahailin Migrating Conservation Base (Dahailing Forestry Bureau, Heilongjiang Province). The seeds were treated with 2% KNO3 for 10h and 0.02% GA3 for 5h immediately after the collection. The germinating rate ((85.33%) of the seeds from Dahailin was obviously higher than that (72.66%) from Changbai Mountains. After being stored at 0-5 (C for 10 months, the seeds were treated again with the same concentration of hormone mentioned above for germination test. The experimental results showed that there was almost no difference in germinating rate between newly collected seeds and 10-month storage seeds, which indicated that low-temperature storage can extend the life of seeds, and that the germinating rate increases with increasing of hormone concentration.

  17. The functions of the endosperm during seed germination.

    Science.gov (United States)

    Yan, Dawei; Duermeyer, Lisza; Leoveanu, Catalina; Nambara, Eiji

    2014-09-01

    In angiosperms, a double fertilization event initiates the development of two distinct structures, the embryo and endosperm. The endosperm plays an important role in supporting embryonic growth by supplying nutrients, protecting the embryo and controlling embryo growth by acting as a mechanical barrier during seed development and germination. Its structure and function in the mature dry seed is divergent and specialized among different plant species. A subset of endospermic tissues are composed of living cells even after seed maturation, and play an active role in the regulation of seed germination. Transcriptome analysis has provided new insights into the regulatory functions of the endosperm during seed germination. It is well known that the embryo secretes signals to the endosperm to induce the degradation of the seed reserve and to promote endosperm weakening during germination. Recent advances in seed biology have shown that the endosperm is capable of sensing environmental signals, and can produce and secrete signals to regulate the growth of the embryo. Thus, germination is a systemic response that involves bidirectional interactions between the embryo and endosperm.

  18. Optimal treatment increased the seed germination of Salvia verticillata L.

    Directory of Open Access Journals (Sweden)

    ALALEH KHAKPOOR

    2015-12-01

    Full Text Available Most seeds of the medicinal species are variable regarding their ecological compatibility with environmental conditions. Therefore, identifying the ecophysiological factors that affect dormancy and create optimal conditions for seed germination of medicinal plants is necessary for their culture and production. To evaluate the effect of different treatments on seed germination of medicinal species of Salvia verticillata, collected in the summer of 2010 in Eastern Azarbaijan, we have performed completely randomized experimental tests with 4 replications. The experimental design of treatment prior to growth included: scrape the skin with sandpaper, treatment with 500 ppm gibberellic acid for 24 and 48 h, treatment with citric acid for 10, 20 and 30 minutes, chilling for 2 and 4 weeks, treatment with warm water at 70°C and control treatment. Results showed that the effect of different treatments was significant on seed germination percent of the medicinal plant Salvia verticillata. Scrape the skin with sandpaper, citric acid treatment for 10, 20 and 30 minutes, and gibberellic acid treatment for 24 hours, increased the germination percentage compared to the control treatment. The most positive impact was observed on the dormancy breaking and germination of medicinal species Salvia verticillata.

  19. Apoptosis in barley aleurone during germination and its inhibition by abscisic acid.

    Science.gov (United States)

    Wang, M; Oppedijk, B J; Lu, X; Van Duijn, B; Schilperoort, R A

    1996-12-01

    During germination of barley grains, DNA fragmentation was observed in the aleurone. The appearance of DNA fragmentation in the aleurone layer, observed by TUNEL staining in aleurone sections, started near the embryo and extended to the aleurone cells far from the embryo in a time dependent manner. The same spatial temporal activities of hydrolytic enzymes such as alpha-amylase were observed in aleurone. DNA fragmentation could also be seen in vitro under osmotic stress, in isolated aleurone. During aleurone protoplast isolation, a very enhanced and strong DNA fragmentation occurred which was not seen in protoplast preparations of tobacco leaves. ABA was found to inhibit DNA fragmentation occurring in barley aleurone under osmotic stress condition and during protoplast isolation, while the plant growth regulator gibberellic acid counteracted the effect of ABA. Addition of auxin or cytokinin had no significant effect on DNA fragmentation in these cells. To study the role of phosphorylation in ABA signal transduction leading to control of DNA fragmentation (apoptosis), the effects of the phosphatase inhibitor okadaic acid and of phenylarisine oxide on apoptosis were studied. We hypothesize that the regulation of DNA fragmentation in aleurone plays a very important role in spatial and temporal control of aleurone activities during germination. The possible signal transduction pathway of ABA leading to the regulation of DNA fragmentation is discussed.

  20. Secondary emission electron gun using external primaries

    Science.gov (United States)

    Srinivasan-Rao, Triveni; Ben-Zvi, Ilan

    2009-10-13

    An electron gun for generating an electron beam is provided, which includes a secondary emitter. The secondary emitter includes a non-contaminating negative-electron-affinity (NEA) material and emitting surface. The gun includes an accelerating region which accelerates the secondaries from the emitting surface. The secondaries are emitted in response to a primary beam generated external to the accelerating region. The accelerating region may include a superconducting radio frequency (RF) cavity, and the gun may be operated in a continuous wave (CW) mode. The secondary emitter includes hydrogenated diamond. A uniform electrically conductive layer is superposed on the emitter to replenish the extracted current, preventing charging of the emitter. An encapsulated secondary emission enhanced cathode device, useful in a superconducting RF cavity, includes a housing for maintaining vacuum, a cathode, e.g., a photocathode, and the non-contaminating NEA secondary emitter with the uniform electrically conductive layer superposed thereon.

  1. Secondary emission electron gun using external primaries

    Science.gov (United States)

    Srinivasan-Rao, Triveni; Ben-Zvi, Ilan; Kewisch, Jorg; Chang, Xiangyun

    2007-06-05

    An electron gun for generating an electron beam is provided, which includes a secondary emitter. The secondary emitter includes a non-contaminating negative-electron-affinity (NEA) material and emitting surface. The gun includes an accelerating region which accelerates the secondaries from the emitting surface. The secondaries are emitted in response to a primary beam generated external to the accelerating region. The accelerating region may include a superconducting radio frequency (RF) cavity, and the gun may be operated in a continuous wave (CW) mode. The secondary emitter includes hydrogenated diamond. A uniform electrically conductive layer is superposed on the emitter to replenish the extracted current, preventing charging of the emitter. An encapsulated secondary emission enhanced cathode device, useful in a superconducting RF cavity, includes a housing for maintaining vacuum, a cathode, e.g., a photocathode, and the non-contaminating NEA secondary emitter with the uniform electrically conductive layer superposed thereon.

  2. Common QTL Affect the Rate of Tomato Seed Germination under Different Stress and Nonstress Conditions

    Science.gov (United States)

    Foolad, Majid R.; Subbiah, Prakash; Zhang, Liping

    2007-01-01

    The purpose of this study was to determine whether the rates of tomato seed germination under different stress and nonstress conditions were under common genetic controls by examining quantitative trait loci (QTL) affecting such traits. Seeds of BC1 progeny of a cross between a slow-germinating tomato breeding line and a rapid-germinating tomato wild accession were evaluated for germination under nonstress as well as cold, salt, and drought stress conditions. In each treatment, the most rapidly-germinating seeds were selected, grown to maturity, and subjected to molecular marker analysis. A selective genotyping approach detected between 6 and 9 QTL affecting germination rate under each of the four conditions, with a total of 14 QTL identified. Ten QTL affected germination rate under 2 or 3 conditions, which were considered germination-related common QTL. Four QTL affected germination rate only in one treatment, which were considered germination-related, condition-specific QTL . The results indicated that mostly the same QTL affected seed germination under different stress and nonstress conditions, supporting a previous suggestion that similar physiological mechanisms contribute to rapid seed germination under different conditions. Marker-assisted selection for the common QTL may result in progeny with rapid seed germinability under different conditions. PMID:18317505

  3. Common QTL affect the rate of tomato seed germination under different stress and nonstress conditions.

    Science.gov (United States)

    Foolad, Majid R; Subbiah, Prakash; Zhang, Liping

    2007-01-01

    The purpose of this study was to determine whether the rates of tomato seed germination under different stress and nonstress conditions were under common genetic controls by examining quantitative trait loci (QTL) affecting such traits. Seeds of BC(1) progeny of a cross between a slow-germinating tomato breeding line and a rapid-germinating tomato wild accession were evaluated for germination under nonstress as well as cold, salt, and drought stress conditions. In each treatment, the most rapidly-germinating seeds were selected, grown to maturity, and subjected to molecular marker analysis. A selective genotyping approach detected between 6 and 9 QTL affecting germination rate under each of the four conditions, with a total of 14 QTL identified. Ten QTL affected germination rate under 2 or 3 conditions, which were considered germination-related common QTL. Four QTL affected germination rate only in one treatment, which were considered germination-related, condition-specific QTL . The results indicated that mostly the same QTL affected seed germination under different stress and nonstress conditions, supporting a previous suggestion that similar physiological mechanisms contribute to rapid seed germination under different conditions. Marker-assisted selection for the common QTL may result in progeny with rapid seed germinability under different conditions.

  4. Effects of KNO3 pretreatment and temperature on seed germination of Sorbus pohuashanensis

    Institute of Scientific and Technical Information of China (English)

    BIAN Lei; YANG Ling; WANG Jian-an; SHEN Hai-long

    2013-01-01

    We characterized the effects of KNO3 pretreatment and germination temperature on dormancy breaking and germination of mature mountain ash seeds.Seeds treated with KNO3 and germinated at 25 ℃followed by 5 ℃ had significantly higher germination percentages and germination potentials (51% and 49%,respectively),compared with controls.These treated seeds also exhibited reduced germination initiation times (minimum of 48 days),and elevated germination rate indices (up to 97).The germination of seeds subjected to long-term cold storage (2 years at 0-5 ℃) was also significantly improved by 3 days of 4%KNO3 pretreatment before germinating under a variable temperature regimen (5 ℃ followed by 25 ℃,and followed by 5 ℃).Germination percentages and germination potentials for these cold-stored seeds reached 67% and 54%,respectively,and the germination rate index increased to 126.99.Pretreatment of mountain ash seeds with KNO3 represents a practical,effective,and pollution-free method for improving germination,and can be implemented easily within a variety of nursery settings.

  5. Mannans and endo-β-mannanases (MAN) in Brachypodium distachyon: expression profiling and possible role of the BdMAN genes during coleorhiza-limited seed germination.

    Science.gov (United States)

    González-Calle, Virginia; Barrero-Sicilia, Cristina; Carbonero, Pilar; Iglesias-Fernández, Raquel

    2015-07-01

    Immunolocalization of mannans in the seeds of Brachypodium distachyon reveals the presence of these polysaccharides in the root embryo and in the coleorhiza in the early stages of germination (12h), decreasing thereafter to the point of being hardly detected at 27h. Concurrently, the activity of endo-β-mannanases (MANs; EC 3.2.1.78) that catalyse the hydrolysis of β-1,4 bonds in mannan polymers, increases as germination progresses. The MAN gene family is represented by six members in the Brachypodium genome, and their expression has been explored in different organs and especially in germinating seeds. Transcripts of BdMAN2, BdMAN4 and BdMAN6 accumulate in embryos, with a maximum at 24-30h, and are detected in the coleorhiza and in the root by in situ hybridization analyses, before root protrusion (germination sensu stricto). BdMAN4 is not only present in the embryo root and coleorhiza, but is abundant in the de-embryonated (endosperm) imbibed seeds, while BdMAN2 and BdMAN6 are faintly expressed in endosperm during post-germination (36-42h). BdMAN4 and BdMAN6 transcripts are detected in the aleurone layer. These data indicate that BdMAN2, BdMAN4 and BdMAN6 are important for germination sensu stricto and that BdMAN4 and BdMAN6 may also influence reserve mobilization. Whether the coleorhiza in monocots and the micropylar endosperm in eudicots have similar functions, is discussed.

  6. External fixators in haemophilia.

    Science.gov (United States)

    Lee, V; Srivastava, A; PalaniKumar, C; Daniel, A J; Mathews, V; Babu, N; Chandy, M; Sundararaj, G D

    2004-01-01

    External fixators (EF) are not commonly used for patients with haemophilia. We describe the use of EF (Ilizarov, AO- uni- and bi-planar fixators and Charnley clamp) in nine patients (mean age: 19.2 years; range: 9-37) with haemophilia for the following indications - arthrodesis of infected joints, treatment of open fractures and osteoclasis. EF required an average of nine skin punctures [range: 4-17 were maintained for a period of 15 weeks (range: 8-29.5), without regular factor replacement, till bone healing was adequate and were removed with a single dose of factor infusion]. The mean preoperative factor level achieved was 85% (range: 64-102%). Much lower levels were subsequently maintained till wound healing. The average total factor consumption was 430 IU kg(-1) (range: 240-870), administered over a period of 17 days (range: 9-44). There were no major complications related to EF except in a patient who developed inhibitors. In conclusion, EF can be used safely in haemophilic patients who do not have inhibitors and does not require prolonged factor replacement.

  7. Wheat cysteine proteases triticain alpha, beta and gamma exhibit mutually distinct responses to gibberellin in germinating seeds.

    Science.gov (United States)

    Kiyosaki, Toshihiro; Asakura, Tomiko; Matsumoto, Ichiro; Tamura, Tomoko; Terauchi, Kaede; Funaki, Junko; Kuroda, Masaharu; Misaka, Takumi; Abe, Keiko

    2009-01-01

    We cloned three novel papain-type cysteine proteases (CPs), triticain alpha, beta and gamma, from 1-d-germinating wheat seeds. Triticain alpha, beta and gamma were constituted with 461, 472 and 365 amino acid residues, respectively, and had Cys-His-Asn catalytic triads as well as signal and propeptide sequences. Triticain gamma contained a putative vacuole-sorting sequence. Phylogenetic analysis showed that these CPs were divided into mutually different clusters. Triticain alpha and gamma mRNAs were expressed in seeds at an early stage of maturation and at the stage of germination 2d after imbibition, while triticain beta mRNA appeared shortly after imbibition. The expression of mRNAs for triticain alpha and gamma was suppressed by uniconazol, a gibberellin synthesis inhibitor. All the three CP mRNAs were strongly expressed in both embryo and aleurone layers. These results suggest that triticain alpha, beta and gamma play differential roles in seed maturation as well as in digestion of storage proteins during germination.

  8. Highly potent germination inhibitors in aqueous eluate of fruits of Bishop's weed (Ammi majus L.) and avoidance of autoinhibition.

    Science.gov (United States)

    Friedman, J; Rushkin, E; Waller, G R

    1982-01-01

    The aqueous eluate from fruits ofAmmi majus (Bishop's weed, Umbelliferae) remarkably inhibited germination of adjacent seeds ofAnastatica hierochuntica, lettuce, or tomato but had no effect on intact fruits ofAmmi. Similar inhibition was found in dark or in light, except that seeds ofA. hierochuntica were significantly more inhibited in the dark than in the light. Xanthotoxin was isolated, identified, and found to account for about a sixth of the inhibitory activity of the eluate. After fruits ofAmmi were submerged in a large volume of water for 4 days, the fruits still exuded enough inhibitors to prevent germination ofA. hierochuntica, lettuce, or tomato. Data support also the proposal that the phytotoxins are compartmentalized between the inner and the outer fruit envelopes. The inner layer excludes inhibitors from the embryo and autotoxicity is thus avoided, whereas the outer one ensures a gradual liberation of the phytotoxic compounds. This, as well as the high reactivity of the eluate, the high densities ofAmmi fruits in nature, and their relatively limited annual germination, suggest chemical inhibition of neighboring plant species other thanAmmi. Hence, in addition to their chemical protection against predators of either lower or higher organisms, furanocoumarins in fruits ofAmmi majus may contribute to its success as a weed.

  9. Effect of fungal and plant metabolites on broomrapes (Orobanche and Phelipanche spp.) seed germination and radicle growth.

    Science.gov (United States)

    Cimmino, Alessio; Fernández-Aparicio, Mónica; Andolfi, Anna; Basso, Sara; Rubiales, Diego; Evidente, Antonio

    2014-10-29

    Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which cause heavy yield losses on important crops. The development of herbicides based on natural metabolites from microbial and plant origin, targeting early stages on parasitic plant development, might contribute to the reduction of broomrape seed bank in agricultural soils. Therefore, the effect of metabolites belonging to different classes of natural compounds on broomrape seed germination and radicle development was assayed in vitro. Among the metabolites tested, epi-sphaeropsidone, cyclopaldic acid, and those belonging to the sesquiterpene class induced broomrape germination in a species-specific manner. epi-Epoformin, sphaeropsidin A, and cytochalasans inhibited germination of GR24-treated broomrape seeds. The growth of broomrape radicle was strongly inhibited by sphaeropsidin A and compounds belonging to cyclohexene epoxide and cytochalasan classes. Broomrape radicles treated with epi-sphaeropsidone developed a layer of papillae while radicles treated with cytochalasans or with sphaeropsidin A turned necrotic. These findings allow new lead natural herbicides for the management of parasitic weeds to be identified.

  10. Seed Germination of selected Taxa from Kachchh Desert, India

    Directory of Open Access Journals (Sweden)

    Vinay Madhukar RAOLE

    2010-06-01

    Full Text Available The district of Kachchh contains many culturally important plants. However, their conservation status is little known due to direct and indirect human activities. This study was undertaken with the aim of contributing to the conservation of the native species of these semi-arid regions through germination trials under laboratory conditions. Mature fruits of ten selected species were collected randomly from the known habitats to obtain viable seeds. These seeds were pre-treated with growth regulators singly or in combination after acid scarification or without scarification. Seeds were found to be dormant due to presence of thick seed coat or due to low level of endogenous hormonal level. Most of these seeds required different storage period to mature. Only seeds of Capparis cartilaginea germinated without treatment while the other species required treatments. Addition of growth regulators has enhanced seed germination in few taxa singly and in some plant cases in combination.

  11. Storage polysaccharides in germinating yellow lupine (Lupinus luteus L.

    Directory of Open Access Journals (Sweden)

    Aleksandra Hoffmannowa

    2014-01-01

    Full Text Available The yellow lupine (Lupinus luteus L. cv. Express was cultured for 16 days in light or in darkness. During the first 3 days of germination starch and hemicelluloses were estimated in the seed organs, cotyledons and axis. Later the estimations were performed daily in cotyledons, shoots and roots of the cultured seedlings. Absence of starch was noted in cotyledons of airdry seeds and an abrupt starch synthesis in the first 24 hours of germination. nation. Degradation of starch, and hemicelluloses in cotyledons of the germinating yellow lupine was rapid and correlated strictly with losses in their dry weight. Similarly to starch synthesis, it showed no light dependence. On the other hand, light influenced synthesis of the studied polysaccharides in the shoot and the root of a develaping lupine seedling.

  12. IV. STORAGE AND GERMINATION TESTS ON SHOREA JAVANICA SEEDS

    Directory of Open Access Journals (Sweden)

    M.I.J. UMBOH

    1987-01-01

    Full Text Available Seeds of Shorea javanica K & V (Dipterocarpaceae, were subjected to different treatments of temperature (27 ± 2°C, 20 ± 2°C and < 10°C, coating (ash and paraffin and relative humidity (20, 66 and 86% and their germination capability as well as moisture content assessed after 3, 7, 14 and 30 days of storage. The germination percentage of the seeds stored 30 days in a cloth bag under different conditions of temperature showed highly significant differences (a = 0.01. No significant differences were found on the effect of coating, duration of storage as well as on the interaction between these two factors. The moisture content of the seeds between 13 and 14% gave a germination percentage above 50% after 30 days.

  13. Seed Germination of selected Taxa from Kachchh Desert, India

    Directory of Open Access Journals (Sweden)

    Vinay Madhukar RAOLE

    2010-06-01

    Full Text Available The district of Kachchh contains many culturally important plants. However, their conservation status is little known due to direct and indirect human activities. This study was undertaken with the aim of contributing to the conservation of the native species of these semi-arid regions through germination trials under laboratory conditions. Mature fruits of ten selected species were collected randomly from the known habitats to obtain viable seeds. These seeds were pre-treated with growth regulators singly or in combination after acid scarification or without scarification. Seeds were found to be dormant due to presence of thick seed coat or due to low level of endogenous hormonal level. Most of these seeds required different storage period to mature. Only seeds of Capparis cartilaginea germinated without treatment while the other species required treatments. Addition of growth regulators has enhanced seed germination in few taxa singly and in some plant cases in combination.

  14. Recycling probability and dynamical properties of germinal center reactions

    CERN Document Server

    Meyer-Hermann, M; Or-Guil, M; Meyer-Hermann, Michael; Deutsch, Andreas; Or-Guil, Michal

    2001-01-01

    We introduce a new model for the dynamics of centroblasts and centrocytes in a germinal center. The model reduces the germinal center reaction to the elements considered as essential and embeds proliferation of centroblasts, point mutations of the corresponding antibody types represented in a shape space, differentiation to centrocytes, selection with respect to initial antigens, differentiation of positively selected centrocytes to plasma or memory cells and recycling of centrocytes to centroblasts. We use exclusively parameters with a direct biological interpretation such that, once determined by experimental data, the model gains predictive power. Based on the experiment of Han et al.(1995) we predict that a high rate of recycling of centrocytes to centroblasts is necessary for the germinal center reaction to work reliably. Furthermore, we find a delayed start of the production of plasma and memory cells with respect to the start of point mutations, which turns to be necessary for the optimization process ...

  15. Effect of electron beam irradiation on seed germination

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seunghee; Bae, Youngmin [Changwon Univ., Changwon (Korea, Republic of)

    2013-07-01

    Effect of electron beam irradiation on seed germination was investigated in this research. Electron beam of 0.5, 1.0, 1.5 and 2.0 kGy was irradiated to the seeds of lettuce, green onion and cucumber, and the irradiated seeds were incubated at 25 .deg. Cn Nitsch medium solidified with 0.2% Phytagel. Germination percentage and the length of the sprouts were determined after 72 hours. Germination percentage of lettuce seeds was greatly reduced by the irradiation, and that of the green onion and cucumber were moderately reduced or unchanged by the irradiation. Although average length of the lettuce sprouts was reduced severely, that of the green onion and cucumber was unchanged or moderately reduced. Conclusively, electron beam irradiation might be a useful way of disinfecting some plant seeds including green onion and cucumber.

  16. Skepticism, contextualism, externalism and modality

    National Research Council Canada - National Science Library

    Ron Wilburn

    2006-01-01

    .... However, because efforts to contextualize externalism via subjunctive conditional analysis court circularity, it is only on an internalistic interpretation that contextualist strategies can even be motivated...

  17. EFFECTS OF LIGHT WAVELENGTHS AND COHERENCE ON BASIDIOSPORES GERMINATION

    Directory of Open Access Journals (Sweden)

    Natalia Poyedinok

    2015-02-01

    Full Text Available The effects of light wavelengths and coherence on basidiospore germination of Agaricus bisporus, Flammulina velutipes, Ganoderma applanatum, Ganoderma lucidum, Hericium erinaceus, Lentinus edodes and Pleurotus ostreatus have been studied. Short-term low-intensity irradiation by coherent (laser light wavelength 488.0 nm and 632.8 nm at doses 45 and 230 mJ/cm2 has significantly increased the number of germinated basidiospores. It has established that there are differences in the photosensitivity not only between species but also between strains. Spores irradiation by 514.5 nm light has been either neutral or inhibitory. A comparative analysis of basidiospores sensitivity to laser and LED light has also been conducted. To stimulate germination of basidiospores and growth of monokaryons the most suitable solution was to use red coherent and incoherent light of 632.8 nm and 660,0 nm for A. bisporus, G. applanatum and P. ostreatus, red and blue coherent light of 632.8 nm and 488,0 nm for F. velutipes, and both red and blue laser and LED light G. lucidum and H. erinaceus and for L. edodes. No essential difference of a continuous wave mode and intermittent mode light effect at the same doses and wavelength on spore germination were revealed. Light influence has reduced germination time and formation of aerial mycelium on agar medium as compared to the original value and increased the growth rate of monosporous isolates. Characterization of basidiospores photosensitivity and development of environmentally friendly stimulating methods of their germination is important for creating highly effective technologies of mushrooms selection and cultivation.

  18. SEED GERMINATION BEHAVIOUR OF THREE ALPINE SPECIES FROM ULUDAĞ MOUNT,TURKEY

    Directory of Open Access Journals (Sweden)

    HülyaARSLAN

    2013-02-01

    Full Text Available In this study, the germination requirements of three species from alpine belt of Uludağ Mount; Gypsophila olympica Boiss., Matthiola montana Boiss. and Silene rhynchocarpa Boiss. We tested thegermination under (20 °C dark, (20 °C continuous light, and photoperiod 20/10 °C (12/12h with distilled water. Different germination behaviour was found for these three species from closely related habitat conditions. G. olympica showed similar germination percentages in dark, light and photoperiod, and germinated faster in light (3.9 days. S. rhyncocarpa germinated 100 % at all the threeconditions but faster in dark with 2.0 days. M. montana seeds were found to require light for germination. The germination was 27.2 % at dark, whereas the seeds were germinated 90 % under photoperiod.The results can be useful for both in situ and ex situ conservation of these plant species.

  19. Transcriptional dynamics of two seed compartments with opposing roles in Arabidopsis seed germination

    NARCIS (Netherlands)

    Dekkers, S.J.W.; Pearce, S.; Bolderen-Veldkamp, R.P.; Marshall, A.; Widera, P.; Gilbert, J.; Drost, H.G.; Bassel, G.; Muller, K.; King, J.R.; Wood, A.; Grosse, I.; Bentsink, L.

    2013-01-01

    Seed germination is a critical stage in the plant life cycle and the first step toward successful plant establishment. Therefore, understanding germination is of important ecological and agronomical relevance. Previous research revealed that different seed compartments (testa, endosperm, and embryo)

  20. Association mapping of germinability and seedling vigor in sorghum under controlled low-temperature conditions

    National Research Council Canada - National Science Library

    Burrell, A. Millie; Upadhyaya, Hari D; Klein, Robert R; Wang, Yi-Hong; Prasad, P.V. Vara; Klein, Patricia E; Sastry, Dintyala V.S.S.R; Morris, Geoffrey P; Dwivedi, Sangam L

    2016-01-01

    ..., sorghum’s sensitivity to low soil temperatures adversely impacts seed germination. In this study, we evaluated the 242 accessions of the ICRISAT sorghum mini core collection for seed germination and seedling vigor at 12...

  1. Germination of guatambu seeds subjected to two light regimes

    Directory of Open Access Journals (Sweden)

    Karina Guollo

    2015-09-01

    Full Text Available Guatambu (Aspidosperma parvifolium A. DC. is a species that faces extinction in different regions of Brazil. The aim of this study was to evaluate the influence of photoperiod on germination of guatambu seeds at 25°C. The statistical procedure used was factorial design with two factors. Factor A was seed lots (Mother tree A, B, and C and factor B was photoperiod (dark and 12 h of photoperiod. Guatambu seeds are not affected by photoperiod condition during the germination process.

  2. The influence of light on the germination of potato seeds

    Directory of Open Access Journals (Sweden)

    A. Listowski

    2015-06-01

    Full Text Available The influence of white and coloured Light and of the darkness on the germination of potato seeds was investigated. Potato seeds germinate in light as well as in darkness. Bed light is stimulative. Far-red and blue light depending of the origin of the seeds populations acted or inhibitive or only as a delaying factor. The after effect of R after FR or FR after R was also studied. The R-FR or FR-R photoreaction observed by potato seeds, differ from the classic pattern established by lettuce and tomato seeds.

  3. Biorregulator on cotton seed germination and initial growth

    OpenAIRE

    Eduardo Pradi Vendruscolo; Heloisa Bueno de Souza; Lucas Alves de Arruda; Sebastião Ferreira de Lima; Rita de Cássia Félix Alvarez

    2015-01-01

    The objective was to evaluate the effect of a bioregulator applied to seeds, on seed germination, emergence and vigor of cotton seedlings. The treatments were a combination of seeds of two cotton cultivars (FMT 701 and FMT 705) exposed to six doses of plant growth regulator: 0.0; 5.0; 10.0; 15.0; 20.0 and 25.0 ml applied 0.5 kg of seed. The experiment was conducted in a completely randomized design in factorial scheme consists of a 2 x 6, with four replications. Germination, initial growth, e...

  4. Characteristics of spore germination and protonemal development in Hypnum pacleseens

    Institute of Scientific and Technical Information of China (English)

    HUANG Shiliang; LI Min; ZHAO Jiancheng; ZHANG Yuanming; WANG Zhenjie

    2006-01-01

    The spore germination,protonemal development,and gametophyte differentiation of Hypnum pacleseens were observed in cultivation.Photomicrographs showed that spore germination of Hypnum pacleseens occured within the exospore.Its protonema is massive with filamentous chloronema formed inside.The terminal part of the chloronema differentiated into filamentous caulonema and its rhizoid was derived from the apical cell of the filamentous chloronema.The initial cell of gametophyte differentiated from chloronema and caulonema.Sporeling type of Hypnum pacleseens is developmentally similar to Glyphmitrium-type.

  5. Containment atmosphere response to external sprays

    Energy Technology Data Exchange (ETDEWEB)

    Green, J.; Almenas, K. [Univ. of Maryland, College Park, MD (United States)

    1995-09-01

    The application of external sprays to a containment steel shell can be an effective energy removal method and has been proposed in the passive AP-600 design. Reduction of the steel shell temperature in contact with the containment atmosphere enhances both heat and mass transfer driving forces. Large scale experimental data in this area is scarce, therefore the measurements obtained from the E series tests conducted at the German HDR facility deserve special attention. These long term tests simulated various severe accident conditions, including external spraying of the hemispherical steel shell. This investigation focuses upon the integral response of the HDR containment atmosphere during spray periods and upon methods by which lumped parameter system codes, like CONTAIN, model the underlying condensation phenomena. Increases in spray water flowrates above a minimum value were ineffective at improving containment pressure reduction since the limiting resistance for energy transfer lies in the noncondensable-vapor boundary layer at the inner condensing surface. The spray created an unstable condition by cooling the upper layers of a heated atmosphere and thus inducing global natural circulation flows in the facility and subsequently, abrupt changes in lighter-than-air noncondensable (J{sub 2}/He) concentrations. Modeling results using the CONTAIN code are outlined and code limitations are delineated.

  6. Effect of germination time on proximate analysis, bioactive compounds and antioxidant activity of lentil (Lens culinaris Medik. sprouts

    Directory of Open Access Journals (Sweden)

    A. Ahmed Fouad

    2015-09-01

    Full Text Available Background. The lentil plant, Lens culinaris L., is a member of the Leguminoceae family and constitutes one of the most important traditional dietary components. The purpose of the current study was to investigate the effects of sprouting for 3, 4, 5 and 6 days on proximate, bioactive compounds and antioxidative characteristics of lentil (Lens culinaris sprouts. Material and methods. Lentil seeds were soaked in distilled water (1:10, w/v for 12 h at room temperature (~25°C, then kept between thick layers of cotton cloth and allowed to germinate in the dark for 3, 4, 5 and 6 days. The nutritional composition, protein solubility, free amino acids, antinutritional factors, bioactive compounds and antioxidant activity of raw and germinated samples were determined using standard official procedures. Results. Sprouting process caused significant (P ≤ 0.05 increases in moisture, protein, ash, crude fiber, protein solubility, free amino acids, total, reducing and nonreducing sugars. However, oil content, antinutritional factors (tannins and phytic acid significantly (P ≤ 0.05 decreased. Results indicated that total essential amino acids of lentil seeds protein formed 38.10% of the total amino acid content. Sulfur-containing amino acids were the first limiting amino acid, while threonine was the second limiting amino acid in raw and germinated lentil seeds. Sprouting process has a positive effect on the essential amino acid contents and protein efficiency ratio (PER of lentil sprouts. Phenolics content increased from 1341.13 mg/100 g DW in raw lentil seeds to 1411.50, 1463.00, 1630.20 and 1510.10 in those samples germinated for 3, 4, 5 and 6 days, respectively. Sprouted seeds had higher DPPH radical scavenging and reducing power activities. Conclusions. Based on these results, sprouting process is recommended to increase nutritive value, and antioxidant activity of lentil seeds.

  7. Quantitative trait loci analysis for rice seed vigor during the germination stage*

    OpenAIRE

    Wang, Zhou-fei; Wang,Jian-fei; Bao, Yong-Mei; Wang, Fu-Hua; Zhang, Hong-sheng

    2010-01-01

    Seed vigor is an important characteristic of seed quality, and rice cultivars with strong seed vigor are desirable in direct-sowing rice production for optimum stand establishment. In the present study, the quantitative trait loci (QTLs) of three traits for rice seed vigor during the germination stage, including germination rate, final germination percentage, and germination index, were investigated using one recombinant inbred line (RIL) population derived from a cross between japonica Dagua...

  8. Common QTL Affect the Rate of Tomato Seed Germination under Different Stress and Nonstress Conditions

    OpenAIRE

    Foolad, Majid R.; Subbiah, Prakash; Zhang, Liping

    2007-01-01

    The purpose of this study was to determine whether the rates of tomato seed germination under different stress and nonstress conditions were under common genetic controls by examining quantitative trait loci (QTL) affecting such traits. Seeds of BC1 progeny of a cross between a slow-germinating tomato breeding line and a rapid-germinating tomato wild accession were evaluated for germination under nonstress as well as cold, salt, and drought stress conditions. In each treatment, the most rapid...

  9. QTL Mapping of Low-Temperature Germination Ability in the Maize IBM Syn4 RIL Population

    OpenAIRE

    Shuaidong Hu; Thomas Lübberstedt; Guangwu Zhao; Michael Lee

    2016-01-01

    Low temperature is the primary factor to affect maize sowing in early spring. It is, therefore, vital for maize breeding programs to improve tolerance to low temperatures at seed germination stage. However, little is known about maize QTL involved in low-temperature germination ability. 243 lines of the intermated B73×Mo17 (IBM) Syn4 recombinant inbred line (RIL) population was used for QTL analysis of low-temperature germination ability. There were significant differences in germination-rela...

  10. ddressing constraints in propagation of Allanblackia spp. through seed sectioning and air layering

    Directory of Open Access Journals (Sweden)

    Ofori D A

    2015-02-01

    Full Text Available Allanblackia species are indigenous to West, East and Central African regions with the potential of providing an alternative source of income for rural populations through sale of seed oil. The species therefore needs to be domesticated to support sustainable production of Allanblackia seed oil. Propagation of Allanblackia parviflora through seed germination and air layering was therefore undertaken. Stratified and non-stratified seeds or seed sections were germinated in sand, plain and black polythene bags. Air layering was undertaken on pollarded shoots growing on 1.5, 4 and 6m stumps using coir dust as the medium. At 90 days, germination of un-stratified seeds showed significant differences for the following treatments; proximal sections (0 – 54%; p < 0.0001, longitudinal sections (0 – 44%, p < 0.0001 and whole seed (13 - 31%, p < 0.0001. Germination of stratified seeds and seed sections also showed significant differences; proximal sections (37 - 53%, p < 0.0001, whole seed (21 - 32%, p < 0.0001. Distal seed sections did not germinate but only produced seed roots. For air layering, rooting success (P < 0.05 declined with increasing stump height from 72% to 21.4% for 1.5m and 6m stumps respectively. The results are discussed in relation to mass propagation of Allanblackia spp. to support large scale cultivation.

  11. Germination, growth rates, and electron microscope analysis of tomato seeds flown on the LDEF

    Science.gov (United States)

    Hammond, Ernest C., Jr.; Bridgers, Kevin; Brown, Cecelia Wright

    1995-01-01

    The tomato seeds were flown in orbit aboard the Long Duration Exposure Facility (LDEF) for nearly six years. During this time, the tomato seeds received an abundant exposure to cosmic radiation and solar wind. Upon the return of the LDEF to earth, the seeds were distributed throughout the United States and 30 foreign countries for analysis. The purpose of the experiment was to determine the long term effect of cosmic rays on living tissue. Our university analysis included germination and growth rates as well as Scanning Electron Microscopy and X-ray analysis of the control as well as Space-exposed tomato seeds. In analyzing the seeds under the Electron Microscope, usual observations were performed on the nutritional and epidermis layer of the seed. These layers appeared to be more porous in the Space-exposed seeds than on the Earth-based control seeds. This unusual characteristic may explain the increases in the space seeds growth pattern. (Several test results show that the Space-exposed seeds germinate sooner than the Earth-Based seeds. Also, the Space-exposed seeds grew at a faster rate). The porous nutritional region may allow the seeds to receive necessary nutrients and liquids more readily, thus enabling the plant to grow at a faster rate. Roots, leaves and stems were cut into small sections and mounted. After sputter coating the specimens with Argon/Gold Palladium Plasma, they were ready to be viewed under the Electron Microscope. Many micrographs were taken. The X-ray analysis displayed possible identifications of calcium, potassium, chlorine, copper, aluminum, silicon, phosphate, carbon, and sometimes sulfur and iron. The highest concentrations were shown in potassium and calcium. The Space-exposed specimens displayed a high concentration of copper and calcium in the two specimens. There was a significantly high concentration of copper in the Earth-based specimens, whereas there was no copper in the Space-exposed specimens.

  12. ExternE transport methodology for external cost evaluation of air pollution

    DEFF Research Database (Denmark)

    Jensen, S. S.; Berkowicz, R.; Brandt, J.

    The report describes how the human exposure estimates based on NERI's human exposure modelling system (AirGIS) can improve the Danish data used for exposure factors in the ExternE Transport methodology. Initially, a brief description of the ExternE Tranport methodology is given and it is summaris...... how the methodology has been applied so far in a previous Danish study. Finally, results of a case study are reported. Exposure factors have been calculated for various urban categories in the Greater Copenhagen Area...

  13. ExternE transport methodology for external cost evaluation of air pollution (DK)

    Energy Technology Data Exchange (ETDEWEB)

    Solvang Jensen, S.; Berkowicz, R.; Brandt, J. [National Environmental Research Inst., Dept. of Atmospheric Environment (Denmark); Willumsen, E.; Kristensen, N.B. [COWI (Denmark)

    2004-07-01

    The report describes how the human exposure estimates based on NERI's human exposure modelling system (AiGIS) can improve the Danish data used for exposure factors in the ExternE Transport methodology. Inititally, a brief description of the ExternE Transport methodology is given and it is summarised how the methodology has been applied so far in a previous Danish study. Finally, results of a case study are reported. Exposure factors have been calculated for various urban categories in the Greater Copenhagen Area. (au)

  14. Artificial seed germination and seedling production ofZostera marina L. by salinity manipulation

    Institute of Scientific and Technical Information of China (English)

    LIU Yunlong; ZHANG Xuelei; SONG Wei; WANG Zongling

    2016-01-01

    Vast declines inZostera marina seagrass beds demand effective methods of rehabilitation. In this study, we developed a practical method by reducing salinity to induce seed germination followed with recovering salinity to facilitate seedling production ofZ. marina. The results showed thatZ. marina seeds collected from natural seawater (salinity 30) were induced to germinate at reduced salinities. Percent germination (GR) was higher and mean-time-to-germinate (MTG) was shorter at lower salinities. The highestGR and shortestMTG occurred at salinity 0 (deionized freshwater). After germination in freshwater, seeds could develop into seedlings at salinities 5–30 and continue the growth. Viability or development of germinated seeds was not significantly different during the 40 d of post-germination incubation at salinities 5–15 after 1–20 d of germination in freshwater. However, during the process of translating germinated seeds from salinity 0 and 5 to salinity 30, reducing the gradients of post-germination acclimation facilitated more seeds forming seedlings in less time. On average, after 60 d of static incubation, including 20 d in freshwater for germination followed with immediate shift to salinity 5 and increasing to salinity 30 at increment of 5 every two days until cultivation at constant salinity 30, 33% ofZ. marina seeds produced healthy seedlings. The results indicate that the salinity-manipulation based method of artificial germination and seedling production is practical and effective in supporting rehabilitation ofZ. marina bed.

  15. Physical characterization of Rhipsalis (Cactaceae) fruits and seeds germination in different temperatures and light regimes.

    Science.gov (United States)

    Lone, A B; Colombo, R C; Andrade, B L G; Takahashi, L S A; Faria, R T

    2016-06-01

    The germination characteristics of the native cactus species are poorly known, being the temperature and the light the factors that the most interferes in that process. Thus, the objective of the present work was to characterize the fruits and evaluate the influence of the temperature and the light in the seed germination of Rhipsalis floccosa, Rhipsalis pilocarpa and Rhipsalis teres. The tested constant temperatures were 15, 20, 25, 30 and 35 °C and the alternate of 20-30 °C and 25-35 °C in a photoperiod of 10 hours, and with determination of the most appropriate temperature, the germination was tested in light absence. The germination percentage, the index of germination speed and medium time of germination were evaluated. For R. floccosa, the highest germination percentage was at 20 °C. For R. pilocarpa and R. teres, the highest germination percentages occurred in 15 °C and 20 °C. There was correlation to germination percentage between the three species, indicating that they had similar germination behavior. Total absence of germination was verified for the three species in condition of light absence. In conclusion, the temperature of 20 °C is the most suitable for the seed germination of R. floccosa. For the species R. pilocarpa and R. teres, the temperatures of 15 and 20 °C are the most suitable.

  16. Physical characterization of Rhipsalis (Cactaceae fruits and seeds germination in different temperatures and light regimes

    Directory of Open Access Journals (Sweden)

    A. B. Lone

    Full Text Available Abstract The germination characteristics of the native cactus species are poorly known, being the temperature and the light the factors that the most interferes in that process. Thus, the objective of the present work was to characterize the fruits and evaluate the influence of the temperature and the light in the seed germination of Rhipsalis floccosa, Rhipsalis pilocarpa and Rhipsalis teres. The tested constant temperatures were 15, 20, 25, 30 and 35 °C and the alternate of 20-30 °C and 25-35 °C in a photoperiod of 10 hours, and with determination of the most appropriate temperature, the germination was tested in light absence. The germination percentage, the index of germination speed and medium time of germination were evaluated. For R. floccosa, the highest germination percentage was at 20 °C. For R. pilocarpa and R. teres, the highest germination percentages occurred in 15 °C and 20 °C. There was correlation to germination percentage between the three species, indicating that they had similar germination behavior. Total absence of germination was verified for the three species in condition of light absence. In conclusion, the temperature of 20 °C is the most suitable for the seed germination of R. floccosa. For the species R. pilocarpa and R. teres, the temperatures of 15 and 20 °C are the most suitable.

  17. Isolation and characterization of the gene encoding the starch debranching enzyme limit dextrinase from germinating barley

    DEFF Research Database (Denmark)

    Kristensen, Michael; Lok, Finn; Planchot, Véronique

    1999-01-01

    expression is high during germination and the steady state transcription level reaches a maximum at day 5 of germination. The deduced amino acid sequence corresponds to the protein sequence of limit dextrinase purified from germinating malt, as determined by automated N-terminal sequencing of tryptic...

  18. The role of water channel proteins and nitric oxide signaling in rice seed germination

    Institute of Scientific and Technical Information of China (English)

    Hong-Yan Liu; Xin Yu; Da-Yong Cui; Mei-Hao Sun; Wei-Ning Sun; Zhang-Cheng Tang; Sang-Soo Kwak; Wei-Ai Su

    2007-01-01

    Previous studies have demonstrated the possible role of several aquaporins in seed germination. But systematic investigation of the role of aquaporin family members in this process is lacking. Here, the developmental regulation of plasma membrane intrinsic protein (PIP) expression throughout germination and post-germination processes in rice embryos was analyzed. The expression patterns of the PIPs suggest these aquaporins play different roles in seed germination and seedling growth. Partial silencing of the water channel genes, OsPIP1; 1 and OsPIP1;3, reduced seed germination while over-expression of OsPIPl;3 promoted seed germination under water-stress conditions. Moreover, spatial expression analysis indicates that OsPIP1;3 is expressed predominantly in embryo during seed germination. Our data also revealed that the nitric oxide (NO) donors, sodium nitroprusside (SNP) and S-nitrosoglutathione (GSNO), promoted seed germination; furthermore, the NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, inhibited germination and reduced the stimulative effects of SNP and GSNO on rice germination. Exogenous NO stimulated the transcription of OsPIP1;1, OsPIP1;2, OsPIP1;3 and OsPIP2;8 in germinating seeds. These results suggest that water channels play an important role in seed germination, acting, at least partly, in response to the NO signaling pathway.

  19. External coating of colonic anastomoses

    DEFF Research Database (Denmark)

    Pommergaard, Hans-Christian; Achiam, Michael Patrick; Rosenberg, Jacob

    2012-01-01

    Colon anastomotic leakage remains both a frequent and serious complication in gastrointestinal surgery. External coating of colonic anastomoses has been proposed as a means to lower the rate of this complication. The aim of this review was to evaluate existing studies on external coating of colonic...

  20. Retrofitting Systems for External Walls

    DEFF Research Database (Denmark)

    Rose, Jørgen

    1997-01-01

    In this report, 9 different external and internal retrofitting systems are analyzed using numerical calculations. The analysis focuses on the thermal bridge effects in the different systems, and on this basis it is discussed whether internal or external retrofitting has the most advantages...

  1. Optimal spore germination in Clostridium botulinum ATCC 3502 requires the presence of functional copies of SleB and YpeB, but not CwlJ.

    Science.gov (United States)

    Meaney, Carolyn A; Cartman, Stephen T; McClure, Peter J; Minton, Nigel P

    2015-08-01

    Germination, the process by which dormant endospores return to vegetative growth, is a critical process in the life cycle of the notorious pathogen Clostridium botulinum. Crucial is the degradation by hydrolytic enzymes of an inner peptidoglycan spore layer termed the cortex. Two mechanistically different systems of cortex lysis exist in spores of Clostridium species. C. botulinum ATCC 3502 harbours the Bacillus-like system of SleB, CwlJ and YpeB cortex lytic enzymes (CLEs). Through the construction of insertional gene knockout mutants in the sleB, cwlJ and ypeB genes of C. botulinum ATCC 3502 and the production of spores of each mutant strain, the effect on germination was assessed. This study demonstrates a reduced germination efficiency in spores carrying mutations in either sleB or ypeB with an approximate 2-fold reduction in heat resistant colony forming units (CFU/OD600) when plated on rich media. This reduction could be restored to wild-type levels by removing the spore coat and plating on media supplemented with lysozyme. It was observed that cwlJ spores displayed a similar germination efficiency as wild-type spores (P > 0.05). An optimal germinant commixture was identified to include a combination of l-alanine with sodium bicarbonate as it resulted in a 32% drop in OD600, while the additional incorporation of l-lactate resulted in a 57% decrease. Studies of the germination efficiency of spores prepared from all three CLE mutants was performed by monitoring the associated decrease in optical density but a germination defect was not observed in any of the CLE mutant strains. This was likely due to the lack of specificity of this particular assay. Taken together, these data indicate that functional copies of SleB and YpeB, but not CwlJ are required for the optimal germination of the spores of C. botulinum ATCC 3502.

  2. Phytochrome and Seed Germination. III. Action of Prolonged Far Red Irradiation on the Germination of Tomato and Cucumber Seeds.

    Science.gov (United States)

    Yaniv, Z; Mancinelli, A L; Smith, P

    1967-11-01

    Prolonged irradiation with continuous or intermittent far red prevents the germination of tomato and cucumber seeds. The inhibitory efficiency of intermittent far red decreases with the lengthening of the interval between successive irradiations, and with the increase of temperature. If each far red irradiation is followed by red, germination is restored. Intermittent far red is less inhibitory than intermittent red-far red when red is given immediately before each far red. This effect is more evident when the interval between successive irradiation becomes longer.

  3. Nonmixing layers

    Science.gov (United States)

    Gaillard, Pierre; Giovangigli, Vincent; Matuszewski, Lionel

    2016-12-01

    We investigate the impact of nonideal diffusion on the structure of supercritical cryogenic binary mixing layers. This situation is typical of liquid fuel injection in high-pressure rocket engines. Nonideal diffusion has a dramatic impact in the neighborhood of chemical thermodynamic stability limits where the components become quasi-immiscible and ultimately form a nonmixing layer. Numerical simulations are performed for mixing layers of H2 and N2 at a pressure of 100 atm and temperature around 120-150 K near chemical thermodynamic stability limits.

  4. Performance Targets and External Benchmarking

    DEFF Research Database (Denmark)

    Friis, Ivar; Hansen, Allan; Vámosi, Tamás S.

    Research on relative performance measures, transfer pricing, beyond budgeting initiatives, target costing, piece rates systems and value based management has for decades underlined the importance of external benchmarking in performance management. Research conceptualises external benchmarking...... the conditions upon which the market mechanism is performing within organizations. This paper aims to contribute to research by providing more insight to the conditions for the use of external benchmarking as an element in performance management in organizations. Our study explores a particular type of external...... towards the conditions for the use of the external benchmarks we provide more insights to some of the issues and challenges that are related to using this mechanism for performance management and advance competitiveness in organizations....

  5. 沙芥种子发芽过程中的解剖结构特征%Anatomical Structure Features of Pugionium cornutum Seeds in Germination Process

    Institute of Scientific and Technical Information of China (English)

    杨忠仁; 贾晋; 郝丽珍; 张卫华; 张凤兰

    2013-01-01

    为了给沙芥种子的萌发研究提供解剖学依据,采用石蜡切片方法观察了沙芥种子萌发过程中的解剖结构变化.结果表明,沙芥种子的种皮结构简单,由两层细胞组成,外层细胞的外壁木质化;播种至萌动露白前的子叶表皮分化出具有贮水功能的体积较大的泡状细胞镶嵌于表皮细胞间,露白至出苗前子叶表皮中的泡状细胞和叶肉组织开始退化.%Anatomical structure changes of P.cornutum seeds in germination process were observed by paraffin section method to provide a anatomical reference or the research on P.cornutum seed germination.The results showed that the seed coat structure was simple and composed of two layers of cells,and the outer wall was lignification; From seed sowing to germination,cotyledon epidermal differentiated to large alveolar cells for stocking water,embedded in the epidermal cells; From germination to seedling,bubbly cells in the cotyledon epidermal and mesophyll tissue began to degenerate.

  6. A microfluidic device for real-time monitoring of Bacillus subtilis bacterial spores during germination based on non-specific physicochemical interactions on the nanoscale level.

    Science.gov (United States)

    Zabrocka, L; Langer, K; Michalski, A; Kocik, J; Langer, J J

    2015-01-07

    A microfluidic device for studies on the germination of bacterial spores (e.g. Bacillus subtilis) based on non-specific interactions on the nanoscale is presented. A decrease in the population of spores during germination followed by the appearance of transition forms and an increase in the number of vegetative cells can be registered directly and simultaneously by using the microfluidic device, which is equipped with a conductive polymer layer (polyaniline) in the form of a nano-network. The lab-on-a-chip-type device, operating in a continuous flow regime, allows monitoring of germination of bacterial spores and analysis of the process in detail. The procedure is fast and accurate enough for quantitative real-time monitoring of the main steps of germination, including final transformation of the spores into vegetative cells. All of this is done without the use of biomarkers or any bio-specific materials, such as enzymes, antibodies and aptamers, and is simply based on an analysis of physicochemical interactions on the nanoscale level.

  7. Proteomes of the barley aleurone layer: A model system for plant signalling and protein secretion.

    Science.gov (United States)

    Finnie, Christine; Andersen, Birgit; Shahpiri, Azar; Svensson, Birte

    2011-05-01

    The cereal aleurone layer is of major importance due to its nutritional properties as well as its central role in seed germination and industrial malting. Cereal seed germination involves mobilisation of storage reserves in the starchy endosperm to support seedling growth. In response to gibberellic acid produced by the embryo, the aleurone layer synthesises hydrolases that are secreted to the endosperm for the degradation of storage products. The barley aleurone layer can be separated from the other seed tissues and maintained in culture, allowing the study of the effect of added signalling molecules in an isolated system. These properties have led to its use as a model system for the study of plant signalling and germination. More recently, proteome analysis of the aleurone layer has provided new insight into this unique tissue including identification of plasma membrane proteins and targeted analysis of germination-related changes and the thioredoxin system. Here, analysis of intracellular and secreted proteomes reveals features of the aleurone layer system that makes it promising for investigations of plant protein secretion mechanisms.

  8. Classification of temperature response in germination of Brassicas

    Science.gov (United States)

    Since soil temperature affects germination and emergence of canola (Brassica napus L.), mustard [B. juncea (L.) Czerniak. and Sinapsis alba L.], and camelina [Camelina sativa (L.) Crantz.], planting dates have to be adjusted to prevent crop failures. These crops can be used as biofuel feedstocks, a...

  9. PICKLE acts during germination to repress expression of embryonic traits

    Science.gov (United States)

    Li, Hui-Chun; Chuang, King; Henderson, James T.; Rider, Stanley Dean; Bai, Yinglin; Zhang, Heng; Fountain, Matthew; Gerber, Jacob; Ogas, Joe

    2008-01-01

    SUMMARY PICKLE (PKL) codes for a CHD3 chromatin remodeling factor that plays multiple roles in Arabidopsis growth and development. Previous analysis of the expression of genes that exhibit PKL-dependent regulation suggested that PKL acts during germination to repress expression of embryonic traits. In this study, we examined the expression of PKL protein to investigate when and where PKL acts to regulate development. A PKL:eGFP translational fusion is preferentially localized in the nucleus of cells, consistent with the proposed role for PKL as a chromatin remodeling factor. A steroid-inducible version of PKL - a fusion of PKL to the glucocorticoid receptor (PKL:GR) - was used to examine when PKL acts to repress expression of embryonic traits. We found that activation of PKL:GR during germination was sufficient to repress expression of embryonic traits in the primary roots of pkl seedlings whereas activation of PKL:GR after germination had little effect. In contrast, we observed that PKL is required continuously after germination to repress expression of PHERES1, a type I MADS box gene that is normally expressed during early embryogenesis in wild-type plants. Thus PKL acts at multiple points during development to regulate patterns of gene expression in Arabidopsis. PMID:16359393

  10. Live-imaging of Bacillus subtilis spore germination and outgrowth

    NARCIS (Netherlands)

    Pandey, R.

    2014-01-01

    Spores of Gram-positive bacteria such as Bacillus and Clostridium cause huge economic losses to the food industry. In food products, spores survive under food preservation conditions and subsequent germination and outgrowth eventually causes food spoilage. Therefore efforts are being made to elimina

  11. Mechanism and control of Genipa americana seed germination

    NARCIS (Netherlands)

    Queiroz, S.E.E.; Silva, da E.A.A.; Davide, A.C.; Jose, A.C.; Silva, A.T.; Fraiz, A.C.R.; Faria, J.M.R.; Hilhorst, H.W.M.

    2012-01-01

    Genipa americana (Rubiaceae) is important for restoration of riparian forest in the Brazilian Cerrado. The objective was to characterize the mechanism and control of germination of G. americana to support uniform seedling production. Morphology and morphometrics of seeds, embryo and endosperm were a

  12. Asymbiotic seed germination and in vitro propagation of ...

    African Journals Online (AJOL)

    Joe Krawczyszyn

    2015-10-13

    Oct 13, 2015 ... seeds, regardless of storage time and storage temperature. Whole leaf and ... subjected to drying (to 5% moisture content) and freezing. (-20°C) ... distilled water. ... 0.1 N NaOH or HCl before the addition of agar. .... There is an increase in germination rate for seeds .... Skoog medium at half-strength of salts.

  13. Influence of gamma irradiation on pollen viability, germination ability ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-15

    Dec 15, 2009 ... cannot fertilize the egg-cell and the polar nuclei. These .... irradiated pollens by sitting drop culture method (Zaman, 2006). The medium was ... and 24 h for germination ability tests of setting the experiment. (Şensoy et al.

  14. Biosynthesis of germination stimulants of parasitic weeds Striga and Orobanche

    NARCIS (Netherlands)

    Sun, Z.

    2008-01-01

    My research focused on the biosynthetic origin of germination stimulants of the root parasitic plants, Striga spp. and Orobanche spp., which have an increasing impact on cereal and other economically important crops in many regions of the world. The traditional control methods are not sufficient and

  15. Stochastic discrete event simulation of germinal center reactions

    NARCIS (Netherlands)

    Figge, MT

    2005-01-01

    We introduce a generic reaction-diffusion model for germinal center reactions and perform numerical simulations within a stochastic discrete event approach. In contrast to the frequently used deterministic continuum approach, each single reaction event is monitored in space and time in order to simu

  16. Fast neutron sensitivity of dry and germinating tomato seeds

    NARCIS (Netherlands)

    Contant, R.B.

    1970-01-01

    A study was made of changes in fast neutron effectiveness during the hydration and germination of tomato seeds. The main findings and conclusions are the following,

    Section 3.6

    Samples of unirradiated seeds and their constituent parts (seedcoat+endosperm and embryo) were taken at short

  17. Bacillus subtilis Spores Germinate in the Chicken Gastrointestinal Tract▿

    OpenAIRE

    Stephen T Cartman; La Ragione, Roberto M.; Woodward, Martin J.

    2008-01-01

    A number of poultry probiotics contain bacterial spores. In this study, orally administered spores of Bacillus subtilis germinated in the gastrointestinal (GI) tracts of chicks. Furthermore, 20 h after spores were administered, vegetative cells outnumbered spores throughout the GI tract. This demonstrates that spore-based probiotics may function in this host through metabolically active mechanisms.

  18. Biorregulator on cotton seed germination and initial growth

    Directory of Open Access Journals (Sweden)

    Eduardo Pradi Vendruscolo

    2015-12-01

    Full Text Available The objective was to evaluate the effect of a bioregulator applied to seeds, on seed germination, emergence and vigor of cotton seedlings. The treatments were a combination of seeds of two cotton cultivars (FMT 701 and FMT 705 exposed to six doses of plant growth regulator: 0.0; 5.0; 10.0; 15.0; 20.0 and 25.0 ml applied 0.5 kg of seed. The experiment was conducted in a completely randomized design in factorial scheme consists of a 2 x 6, with four replications. Germination, initial growth, emergency speed index and seedling emergence were evaluated. Cotton cultivars FMT 701 and FMT 705 differently respond to application of plant growth regulator on seed. The application of plant growth regulator to FMT 701 cultivar cotton seeds did not affect germination, resulted in less vigorous seedlings and reduction in its emergence. For FMT 705 cultivar, the dose of 25 mL produced more vigorous seedlings, reduced seedling emergence, but did not affect seed germination.

  19. Proteomic analysis of Arabidopsis seed germination and priming

    NARCIS (Netherlands)

    Gallardo, K.; Job, C.; Groot, S.P.C.; Puype, M.; Demol, H.; Vandekerckhove, J.; Job, D.

    2001-01-01

    To better understand seed germination, a complex developmental process, we developed a proteome analysis of the model plant Arabidopsis for which complete genome sequence is now available. Among about 1,300 total seed proteins resolved in two-dimensional gels, changes in the abundance (up- and down-

  20. Conditions and Stimulation for Germination in Glycyrrhiza uralensis Fisch Seeds

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Evaluation of seed quality is the key to seed distributing and seeding of Glycyrrhiza uralensis Fisch, as an important species for pharmacy and soil conservation. Here, we study the effects of light and temperature on seed germination and mechanical and chemical scarification on breaking the seed coat. Seeds were collected in 2004, 2005, and 2006, placed in Petri dishes, and incubated at constant temperature 20, 25, and 30℃, and alternating temperature 15-25, 20-30, 15-30, and 20-35℃ under either an 8 h photoperiod or total darkness for 28 consecutive days. Different methods were used to break the dormancy owing to hard seededness in this species such as chemical scarification by immersing in concentrated sulphuric acid for 5, 10, 15, 20, 25, 30, 45, and 60 min, in 0.2% KNO3 solution to saturate the seedbed, and prechilling for 7 d at 7℃ and mechanical scarification by cutting. The results showed that alternating temperature at 20-30℃ with 8 h photoperiod and 16 h darkness was optimum for G. Uralensis seed germinating in the laboratory. Hard seeds were broken by concentrated sulphuric acid soaking or mechanical scarification by cutting. Germination of seeds harvested in two different years was both promoted by immersing for 30-45 min in concentrated sulphuric acid. KNO3 solution was ineffective for reducing hard seeds. During seed germinating, the first count was on the 7th day and the last count was on the 14th day.

  1. Environmental factors for germination of Sclerotinia sclerotiorum sclerotia

    Science.gov (United States)

    Basal stalk rot of sunflower is an economically important and rather unique disease among crops that are susceptible to Sclerotinia sclerotiorum. This disease is the result of myceliogenic germination of sclerotia whereby the vegetative hyphae infect the sunflower below the soil level. In contrast, ...

  2. Sugar signalling during germination and early seedling establishment in Arabidopsis

    NARCIS (Netherlands)

    Dekkers, S.J.W.

    2006-01-01

    Sugars have pronounced effects on many plant processes like gene expression, germination and early seedling development. Several screens for sugar insensitive mutants were performed to identify genes involved in sugar response pathways using the model plant Arabidopsis. These include sun, gin and si

  3. Effects of water stress and seed mass on germination and ...

    African Journals Online (AJOL)

    enoh

    2012-03-01

    Mar 1, 2012 ... important restriction factors to seed germination because of the delay in its initiation or ... has little rain, resulting in water as a limiting factor to plant growth. ..... The influence of seed size, shape and treatment on inbred seed ...

  4. Characterization of germination receptors of Bacillus cereus ATCC 14579

    NARCIS (Netherlands)

    Hornstra, L.M.; Vries, de Y.P.; Wells-Bennik, M.H.J.; Vos, de W.M.; Abee, T.

    2006-01-01

    Specific amino acids, purine ribonucleosides, or a combination of the two is required for efficient germination of endospores of Bacillus cereus ATCC 14579. A survey including 20 different amino acids showed that L-alanine, L-cysteine, L-threonine, and L-glutamine are capable of initiating the germi

  5. A simple staining method for observation of germinated Striga seeds

    NARCIS (Netherlands)

    Shusheng Long,; Lendzemo, V.W.; Kuyper, T.W.; Zhengsheng Kang,; Vierheilig, H.; Steinkellner, S.

    2008-01-01

    In vitro techniques are essential for Striga research and the development of appropriate control methods. In the laboratory, pre-screening of non-host or false-host plants of Striga for trap cropping or the screening of hosts for resistance involves visual evaluation of Striga seed germination that

  6. Spatial model of affinity maturation in germinal centers

    NARCIS (Netherlands)

    Kesmir, C.; Boer, R.J. de

    2003-01-01

    Affinity maturation of humoral responses to T-cell-dependent antigens occurs in germinal centers (GC). In GCs antigen-specific B cells undergo rounds of somatic mutations that alter their affinity. High-affinity mutants take over GCs very soon after they appear; the replacement rate is as high as 4

  7. Germination strategy of the East African savanna tree Acacia tortilis

    NARCIS (Netherlands)

    Loth, P.E.; Boer, de W.F.; Heitkönig, I.M.A.; Prins, H.H.T.

    2005-01-01

    Germination of Acacia tortilis seeds strongly depends on micro-site conditions. In Lake Manyara National Park, Tanzania, Acacia tortilis occurs abundantly in recently abandoned arable fields and in elephant-mediated gaps in acacia woodland, but does not regenerate in grass swards or beneath

  8. Inhibitory effects of monoterpenes on seed germination and seedling growth.

    Science.gov (United States)

    Kordali, Saban; Cakir, Ahmet; Sutay, Sunay

    2007-01-01

    Monoterpenes, the chemical constituents of essential oils found in plants, are known biologically active compounds. The present study was conducted to investigate the inhibitory effects of 30 monoterpenes including monoterpene hydrocarbons and oxygenated monoterpenes on seed germination and seedling growth of Amaranthus retroflexus, Chenopodium album and Rumex crispus under laboratory conditions. The monoterpenes were applied at contents of 10 and 20 microl for liquid compounds and 10 and 20 microg for solid compounds. The results show that most of the monoterpenes significantly inhibited seed germination and seedling growth of the tested plants. Oxygenated monoterpenes including beta-citronellol, nerol and terpinen-4-ol completely inhibited seed germination and seedling growth of all tested plants. Their inhibitory effects were also stronger than that of the herbicide 2,4-D. In general, monoterpenes were less effective against seed germination and seedling growth of C. album as compared with R. crispus and A. retroflexus. Phytotoxic effects of monoterpene hydrocarbons were found to be lower than those of oxygenated monoterpenes. The alcohol derivatives of oxygenated monoterpenes were also found to be more phytotoxic as compared with their acetate derivatives. Based on the present results, it can be concluded that the oxygenated monoterpenes can be used as potential bio-herbicides.

  9. The maturation and germination of Phytophthora ramorum Chlamydospores

    Science.gov (United States)

    Aaron L. Smith; Everett M. Hansen

    2008-01-01

    Chlamydospores are a distinctive feature of Phytophthora ramorum. They are formed quickly in agar, and within colonized leaves. We followed their development and maturation in vitro and in vivo, and studied conditions affecting their germination. Cell walls of mature P. ramorum chlamydospores...

  10. Chaparral & Fire Ecology: Role of Fire in Seed Germination.

    Science.gov (United States)

    Steele, Nancy L. C.; Keeley, Jon E.

    1991-01-01

    An activity that incorporates the concepts of plant structure and function and ecology is described. Students investigate the reasons why some California chaparral seeds germinate only after a fire has burned the surrounding chaparral. The procedure, discussion and analysis questions, expected results, potential problems, and additional activities…

  11. Aspects of the barley seed proteome during development and germination

    DEFF Research Database (Denmark)

    Finnie, Christine; Maeda, K.; Østergaard, O.;

    2004-01-01

    Analysis of the water-soluble barley seed proteome has led to the identification of proteins by MS in the major spots on two-dimensional gels covering the pi ranges 4-7 and 6-11. This provides the basis for in-depth studies of proteome changes during seed development and germination, tissue...

  12. Chaparral & Fire Ecology: Role of Fire in Seed Germination.

    Science.gov (United States)

    Steele, Nancy L. C.; Keeley, Jon E.

    1991-01-01

    An activity that incorporates the concepts of plant structure and function and ecology is described. Students investigate the reasons why some California chaparral seeds germinate only after a fire has burned the surrounding chaparral. The procedure, discussion and analysis questions, expected results, potential problems, and additional activities…

  13. Biosynthesis of germination stimulants of parasitic weeds Striga and Orobanche

    NARCIS (Netherlands)

    Sun, Z.

    2008-01-01

    My research focused on the biosynthetic origin of germination stimulants of the root parasitic plants, Striga spp. and Orobanche spp., which have an increasing impact on cereal and other economically important crops in many regions of the world. The traditional control methods are not sufficient and

  14. Response of soybean seed germination to cadmium and acid rain.

    Science.gov (United States)

    Liu, Ting Ting; Wu, Peng; Wang, Li Hong; Zhou, Qing

    2011-12-01

    Cadmium (Cd) pollution and acid rain are the main environmental issues, and they often occur in the same agricultural region. Nevertheless, up to now, little information on the combined pollution of Cd(2+) and acid rain action on crops were presented. Here, we investigated the combined effect of Cd(2+) and acid rain on the seed germination of soybean. The results indicated that the single treatment with the low level of Cd(2+) (0.18, 1.0, 3.0 mg L(-1)) or acid rain (pH ≥3.0) could not affect the seed germination of soybean, which was resulted in the increased activities of peroxidase and catalase. The single treatment with the high concentration of Cd(2+) (>6 mg L(-1)) or acid rain at pH 2.5 decreased the activities of peroxidase and catalase, damaged the cell membrane and then decreased the seed germination of soybean. Meanwhile, the same toxic effect was observed in the combined treatment with Cd(2+) and acid rain, and the combined treatment had more toxic effect than the single treatment with Cd(2+) or acid rain. Thus, the combined pollution of Cd(2+) and acid rain had more potential threat to the seed germination of soybean than the single pollution of Cd(2+) or acid rain.

  15. Homeopathically prepared gibberellic acid and barley seed germination.

    Science.gov (United States)

    Hamman, B; Koning, G; Lok, K Him

    2003-07-01

    The potentisation process by which homeopathic preparations are produced raises the concern that these medicines have placebo effects only, since they theoretically no longer contain active molecules of the diluted substance. Plant models offer a method of examining the efficacy of homeopathically prepared solutions. This study examined the effects of homeopathically prepared gibberellic acid (HGA3) on the germination performance of barley (Hordeum vulgare L.) seeds. The effect of HGA3 (4-200 cH) on seed germination rate and seedling development was compared to that of the most commonly used form of gibberellic acid (GA3), 0.5 g l(-1), and control (distilled water). The extent and type of response was dependent on the vigour level of the seedlot. Treating seeds from three vigour groups in HGA3 consistently resulted in larger seedlings. High-vigour seeds treated with HGA3 4, 30 and 200 cH germinated faster, and roots of medium-vigour seedlots treated in HGA3 15 cH were longer. Biphasic effects of HGA3 were also demonstrated. As a plant model, germinating barley seeds successfully demonstrated the ability of HGA3 to produce a biological response.

  16. Seed germination in Miconia theaezans (Bonpl. Cogniaux (Melastomataceae

    Directory of Open Access Journals (Sweden)

    Simone Godoi

    2007-07-01

    Full Text Available The effects of light and temperature were studied on the seeds of Miconia theazeans by isothermic and alternating temperature incubations. The optimum temperature for seed germination was determined by final percentage and germination rates as located in the range of 27.5 to 30 °C and by germination kinetics at the range of 19.5 to 30 °C. The germination was dependent on diffusion processes. The minimum and maximum temperatures were 12.5-15°C and 32.5-35°C, respectively. The seeds showed strong light dependence for germination with the necessity of daily 4-6 h white light irradiation for the maximum induction of germination. However, under 30-20 °C alternating temperatures, daily 2 hours white light was enough to induce germination and attained maximum under 4 h photoperiod. The results indicated that M. theazeans presented characteristics of early successional species.O efeito da luz e da temperatura na germinação de sementes de Miconia theazeans foi analisado através de incubações isotérmicas e de alternâncias de temperaturas. Através das porcentagens finais e velocidade de germinação concluímos que a temperatura ótima de germinação localizaram-se entre 27,5 e 30 °C e pela cinética de germinação verificamos que entre 19,5 e 30 °C a germinação é dependente de processos de difusão. As temperaturas mínima e máxima foram de 12,5-15 °C e 32,5-35 °C, respectivamente. As sementes apresentaram forte dependência da presença de luz branca para a indução da germinação com a necessidade de 4-6 horas de luz diária para a máxima indução do processo. Entretanto, com a alternância de temperaturas de 30 e 20 °C, fotoperíodo de 2 horas foi suficiente para a indução da germinação sendo o máximo de indução obtida a partir de 4 horas diárias. Estes resultados indicam que Miconia theazeans é uma espécie importante que coloniza clareiras e áreas perturbadas em uma floresta natural.

  17. Variability in germination and germination dynamics of differently treated seeds of Serbian spruce (Picea omorika Pančić/Purkynĕ

    Directory of Open Access Journals (Sweden)

    Cvjetković Branislav

    2013-01-01

    Full Text Available Genetic-physiological approach was used in the study of the quality of Serbian spruce seed (Picea omorika /Pančić/Purkynĕ, collected in the populations on the left bank of the river Drina. The seed originated from the three populations that represent the overall ecological and productive conditions of Serbian spruce populations in Bosnia and Herzegovina. Two natural populations were selected: Veliki Stolac and Gostilj, and one planted forest population in Srebrenica. The cones were collected in late autumn 2009 and early spring 2010. They were collected from five trees from Srebrenica and Gostilj, and seven trees from Veliki Stolac. Immediately after they were collected, the cones and seeds were processed and germination tests were done. Germination, germination viability and germination dynamics were studied in three categories of seed treatment: 1 control unit (just processed seed, 2 seed stored for six months at 0-4 ºC, 3 seed stored for seven months at 0-4º C and treated with fungicide after five months of storing. The number of germinated seed was observed and noted on the third, fourth, fifth, seventh, tenth, fourteenth, twenty-first and twenty-eighth day. There were significant differences in germination dynamics at the population level and the level of treatment during the first couple of days of germination test. Fungicide (captan acted as an inhibitor on seed germination process. The seeds originating from the largest population of Veliki Stolac showed the best response to storing treatment with fungicide related to germination dynamics. The seed originating from Srebrenica andkept at low temperatures 0-4 °C without treatment with fungicides showed the best result in germination. Regardless of the presence of differences in the dynamics of germination, significant differences in germination regarding different treatments on the last day of the test, were not recorded.

  18. External costs related to power production technologies. ExternE national implementation for Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Schleisner, L.; Sieverts Nielsen, P.

    1997-12-01

    The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results; to aggregate these site- and technology-specific results to more general figures. The current report covers the results of the national implementation for Denmark. Three different fuel cycles have been chosen as case studies. These are fuel cycles for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant based on biogas. The report covers all the details of the application of the methodology to these fuel cycles aggregation to a national level. (au) EU-JOULE 3. 59 tabs., 25 ills., 61 refs.

  19. Germination of white radish, buckwheat and qing-geng-cai under low pressure in closed environment.

    Science.gov (United States)

    Hinokuchi, Tsutomu; Oshima, Satoshi; Hashimoto, Hirofumi

    2004-11-01

    In order to cultivate plants under low pressure in closed environment, the germination rate of seeds of white radish was investigated under low pressure, low oxygen partial pressure and condition of pure oxygen. The result of these experiments showed that the germination rate was affected by the oxygen partial pressure. From this fact, it is possible to lower the total pressure by using only the pure oxygen in germination. Furthermore, the germination rates of seeds of buckwheat and qing-geng-cai were also investigated in pure oxygen for the comparison. Consequently, though tendency in germination rate of white radish was similar to qing-geng-cai, it was different from buckwheat.

  20. Cellular recycling of proteins in seed dormancy alleviation and germination

    Directory of Open Access Journals (Sweden)

    Krystyna Oracz

    2016-07-01

    Full Text Available Each step of the seed-to-seed cycle of plant development including seed germination is characterized by a specific set of proteins. The continual renewal and/or replacement of these biomolecules are crucial for optimal plant adaptation. As proteins are the main effectors inside the cells, their levels need to be tightly regulated. This is partially achieved by specific proteolytic pathways via multicatalytic protease complexes defined as 20S and 26S proteasomes. In plants, the 20S proteasome is responsible for degradation of carbonylated proteins, while the 26S being a part of ubiquitin-proteasome pathway (UPP is known to be involved in proteolysis of phytohormone signaling regulators. On the other hand, the role of translational control of plant development is also well documented, especially in the context of pollen tube growth and light signaling. Despite the current progress that has been made in seed biology, the sequence of cellular events that determine if the seed can germinate or not are still far from complete understanding. The role and mechanisms of regulation of proteome composition during processes occurring in the plant’s photosynthetic tissues have been well characterized since many years, but in nonphotosynthetic seeds it has emerged as a tempting research task only since the last decade. This review discusses the recent discoveries providing insights into the role of protein turnover in seed dormancy alleviation, and germination, with a focus on the control of translation and proteasomal proteolysis. The presented novel data of translatome profiling in seeds highlighted that post-transcriptional regulation of germination results from a timely regulated initiation of translation. In addition, the importance of 26S proteasome in the degradation of regulatory elements of cellular signaling and that of the 20S complex in proteolysis of specific carbonylated proteins in hormonal- and light-dependent processes occurring in seeds is

  1. The contribution of germinal mosaicism to human aneuploidy.

    Science.gov (United States)

    Ghevaria, Harita; SenGupta, Sioban; Sarna, Urvashi; Sargeant, Susannah; Serhal, Paul; Delhanty, Joy

    2014-01-01

    Germinal mosaicism in a parent is considered to be a rare cause of aneuploidy in the offspring. The aim of this study was to assess the incidence of pre-meiotic errors, indicative of germinal mosaicism, leading to aneuploidy compared with those that occur at meiosis I. The material consisted of 126 oocytes, unexposed to sperm, donated by 57 women with an average maternal age of 35. The oocytes were at various stages of maturity and were analysed by array comparative genomic hybridisation. Of these, 102 gave conclusive results, comprising 47 that were immature, at the germinal vesicle (GV) or metaphase I stage (MI); 34 complete metaphase II-first polar body (MII-PB) complexes together with 21 incomplete complexes. Oocytes at the GV or MI stage provide direct evidence of pre-meiotic aneuploidy. Complete MII-PB complexes with the expected reciprocal gains/losses provide information on MI errors; those with non-reciprocal gains have pre-meiotic errors. Overall, 29 oocytes were aneuploid, and the source of the error was known for 21. In 8 (from 7 women) the error was pre-meiotic consisting of 4 MI oocytes and 4 MII-PB complexes with non-reciprocal gains. The remaining 13 were the result of errors at meiosis I. Although pre-meiotic errors occurred in only 10% of informative oocytes, most notable was the fact that for those oocytes where the source of the error was known, 38% were caused by germinal mosaicism compared with 62% that were the outcome of a meiosis I error. None of the women with germinal mosaicism were infertile.

  2. Proteomic Analysis of Lettuce Seed Germination and Thermoinhibition by Sampling of Individual Seeds at Germination and Removal of Storage Proteins by Polyethylene Glycol Fractionation1

    Science.gov (United States)

    Song, Bin-Yan; Deng, Zhi-Jun; Wang, Yue; Liu, Shu-Jun; Møller, Ian Max; Song, Song-Quan

    2015-01-01

    Germination and thermoinhibition in lettuce (Lactuca sativa ‘Jianyexianfeng No. 1’) seeds were investigated by a proteomic comparison among dry seeds, germinated seeds at 15°C, at 15°C after imbibition at 25°C for 48 h, or at 25°C in KNO3 (all sampled individually at germination), and ungerminated seeds at 25°C, a thermoinhibitory temperature. Before two-dimensional gel electrophoresis analysis, storage proteins (greater than 50% of total extractable protein) were removed by polyethylene glycol precipitation, which significantly improved the detection of less abundant proteins on two-dimensional gels. A total of 108 protein spots were identified to change more than 2-fold (P ethylene production, lipid mobilization, cell elongation, and detoxification of aldehydes were revealed to be potentially related to lettuce seed germination and thermoinhibition. Accumulation of three proteins and expression of five genes participating in the mevalonate (MVA) pathway of isoprenoid biosynthesis correlated positively with seed germinability. Inhibition of this pathway by lovastatin delayed seed germination and increased the sensitivity of germination to abscisic acid. MVA pathway-derived products, cytokinins, partially reversed the lovastatin inhibition of germination and released seed thermoinhibition at 25°C. We conclude that the MVA pathway for isoprenoid biosynthesis is involved in lettuce seed germination and thermoinhibition. PMID:25736209

  3. External fuel thermionic reactor system.

    Science.gov (United States)

    Mondt, J. F.; Peelgren, M. L.

    1971-01-01

    Thermionic reactors are prime candidates for nuclear electric propulsion. The national thermionic reactor effort is concentrated on the flashlight concept with the external-fuel concept as the backup. The external-fuel concept is very adaptable to a completely modular power subsystem which is attractive for highly reliable long-life applications. The 20- to 25-cm long, externally-fueled converters have been designed, fabricated, and successfully tested with many thermal cycles by electrical heating. However, difficulties have been encountered during encapsulation for nuclear heated tests and none have been started to date. These nuclear tests are required to demonstrate the concept feasibility.

  4. Combination of external loads

    Energy Technology Data Exchange (ETDEWEB)

    Frandsen, S.; Tarp Johansen, N.J.; Joergensen, H. [Forskningscenter Risoe, Roskilde (Denmark); Gravesen, H.; Soerensen, S.L. [Carl Bro, Glostrup (Denmark); Pedersen, J. [Elsam Engineering, Fredericia (Denmark); Zorn, R.; Hvidberg Knudsen, M. [DHI Water and Environment, Hoersholm (Denmark); Voelund, P. [Energi E2, Koebenhavn (Denmark)

    2003-09-01

    The project onbectives have been: To improve and consequently opimise the basis for design of offshore wind turbines. This is done through 1) mapping the wind, wave ice and current as well as correlations of these, and 2) by clarifyring how these external conditions transform into loads. A comprehensive effort has been made to get a thorough understanding of the uncertainties that govern the reliability of wind turbines with respect to wind and wave loading. One of the conclusions is that the reliability of wind turbines is generally lower, than the average reliability of building structures that are subject not only to environmental loads, which are very uncertain, but also imposed loads and self weight, which are less uncertain than the environmental loads. The implication is that, at the moment lower load partial safety factors for onshore wind turbines cannot be recommended. For the combination of wind and wave design loads the problem is twofold: 1). A very conservative design will be generated by simply adding the individual wind and wave design loads disregarding the independence of the short-term fluctuations of wind and wave loads. 2). Characteristic values and partial safety factors for wind and wave loads are not defined similarly. This implies that the reliability levels of turbine support structures subject to purely aerodynamic loads and subject to purely hydrodynamic loads are not identical. For the problem of combining aerodynamic design loads and hydrodynamic design loads two results have been obtained in the project: 1). By simple means a site specific wave load safety factor rendering the same safety level for hydrodynamic loads as for aerodynamic loads is derived, and next, by direct square summation of extreme fluctuations, the wind and wave load safety factors are weighted. 2). Under the assumptions that a deep water site is considered and that the wave loading is a fifty-fifty mix of drag and inertia the same wind and wave load safety factor

  5. Maternal habitat affects germination requirements of Anabasis setifera, a succulent shrub of the Arabian deserts

    Directory of Open Access Journals (Sweden)

    Ali El-Keblawy

    2016-03-01

    Full Text Available The effects of maternal habitat on light and temperature requirements during germination were assessed for the succulent desert shrub Anabasis setifera. Seeds were collected from the Mediterranean habitats of Egypt and the hyper-arid subtropical habitats of the United Arab Emirates (UAE. Seeds from the two populations were germinated in three temperature treatments in both a light/dark regime and continuous darkness. Seeds from the Egyptian population germinated significantly greater and faster than those of UAE. Seeds stored for four months at room temperatures have little dormancy and germinate at wide range of temperatures and light conditions, but seeds stored four months in the natural habitat lost their ability to germinate and rotted 10 days after incubation. The germination response to temperature depended on the habitat type. Seeds of the Egyptian population attained a significantly greater germination at lower temperatures, compared with seeds from the UAE population, but there was no difference in germination between the two populations at higher temperatures. Germination of A. setifera was very fast; most seeds germinated within four days. These results reflect the adaptive strategy of germination in both populations, and may help explain the wide distribution of this species in different climatic regions.

  6. Effect of Salinity on Germination and Seedling Growth of Four Medicinal Plants

    Directory of Open Access Journals (Sweden)

    A Dadkhah

    2012-07-01

    Full Text Available This experiment was conducted in germinator in order to study the effects of water potential on seed germination, rate of germination and seedlings growth of four medicinal plants (Coriandrum sativum, Plantago psyllium, Discorinia sophia and Portulaca oleracea. Four water potential inclouding distilled water as control (0, -0.37, -0.59 and –0.81 Mpa which made by different salts (NaCl, CaCl2 and NaCl+CaCl2 in 5 to 1 molar ratio. The experiment was carried out based on completly randomized design with six replications. Results showed that the effects of water potential, type of salt on germination percentage, rate of germination, root and shoot length were significant. With decreasing water potential, germination percentage and rate of germination declined but the response of plant were differ. Germination of Portulaca oleracea was not affected by decreasing water potential where as other significantly decreased. The effect of salt composition was significant on rate and percentage germination. The percentage of germination at lower water potential (–0.37 MPa which made by NaCl + CaCl2 significantly was higher than the same water potential made by only NaCl and CaCl2. Although, percentage and rate germination of Portulaca oleracea were not affected by different water potential, seedling growth of Portulaca oleracea significantly decreased.

  7. Enhancement of seed germination in Macaranga peltata for use in tropical forest restoration

    Institute of Scientific and Technical Information of China (English)

    Cassie R. Rodrigues; Bernard F. Rodrigues

    2014-01-01

    We used pre-sowing treatments viz., soaking seeds in concen-trated sulphuric acid (CSA), gibberellic acid (GA), combined treatment of CSA+GA and mechanical scarification to overcome seed dormancy and enhance synchronous germination of Macaranga peltata seeds. We analysed percent seed germination data by logistic regression and con-firmed that except in GA treatment, time and acid concentration together were crucial for enhancing germination. The combination treatment of CSA and GA resulted in higher percent germination (up to 74%) than either treatment used separately, but produced defective seedlings (26%). Mechanical scarification of seed coat had the greatest impact in enhanc-ing germination (78%) and reducing imbibition time (6 days) against the control (0%). Germination studies and SEM analysis confirmed that seed germination in M. peltata was inhibited by seed coat dormancy.

  8. Phytochrome Control of Germination of Rumex crispus L. Seeds Induced by Temperature Shifts.

    Science.gov (United States)

    Taylorson, R B; Hendricks, S B

    1972-12-01

    High germination of curly dock (Rumex crispus L.) seeds is evident after suitable imbibition and temperature shift treatment, but germination at constant temperatures fails without an input of far red-absorbing form of phytochrome. Preliminary imbibitions at high temperatures (30 C) sharply reduce germination induced by temperature shifts. High germination may be restored by low energies of red radiation, or by brief far red adequate for the photosteady state. Prolonged far red during imbibition also nullifies temperature shift-induced germination. After prolonged far red, high germination may be restored by red radiation of an energy dependent upon the duration of the far red treatment. The evidence supports the conclusion that dark germination induced by temperature shifts arises from the interaction of pre-existent far red-absorbing form of phytochrome in the mature seeds with the temperature shift.

  9. Germination dramatically increases isoflavonoid content and diversity in chickpea (Cicer arietinum L.) seeds.

    Science.gov (United States)

    Wu, Ziyun; Song, Lixia; Feng, Shengbao; Liu, Yuancai; He, Guangyuan; Yioe, Yoecelyn; Liu, Shao Quan; Huang, Dejian

    2012-09-05

    The effect of germination on bioactive components in legume seeds was investigated in terms of the antioxidant capacity and total phenolic contents. Germination increased the total phenolic content and antioxidant capacity of most seeds. Particularly in chickpea seeds, the isoflavone contents increased by over 100 fold, mainly due to the increase of formononetin and biochanin A level. As a result, these two compounds were conveniently isolated from the germinated seeds in preparative scale and structurally confirmed by UV-vis, ESI-MS, and (1)H NMR spectroscopies. Isoflavonoid fingerprints analyzed by HPLC-PDA and LC-ESI-MS demonstrated that germination could significantly increase isoflavonoids diversity. Twenty-five isoflavonoids were detected and identified tentatively. These include 20 isoflavones, 2 isoflavanones, and 3 pterocarpan phytoalexins. Total isoflavonoid content of germinated chickpea was approximately 5-fold of that of germinated soybean. Our findings suggest that the germinated chickpea seeds could serve as a promising functional food rich in isoflavonoids.

  10. BIOSECURITY FOR REDUCING OCHRATOXIN A PRODUCTIVITY AND THEIR IMPACT ON GERMINATION AND ULTRASTRUCTURES OF GERMINATED WHEAT GRAINS

    Directory of Open Access Journals (Sweden)

    M.M.

    2012-08-01

    Full Text Available Ochratoxin A (OTA is a secondary metabolite of some fungi that causes very serious problems for plants, animals and humans. Various microorganisms such as bacteria and microscopic fungi have been tested for their abilities to prevent ochratoxin A contamination or detoxify foods. In this study, Saccharomyces cerevisiae and Lactobacillus bulgaricus reduced OTA production by Aspergillus ochraceus to 40.88 µg/ml ( productivity 60.69% and 13.80 µg/ml (productivity 20.48% respectively compared with the control (67.35 µg/ml (productivity 100%. The results clearly indicated that the seed germinibility in the presence of OTA was decreased with increasing concentration, whereas the germinibility was uncompletely ceased at high concentration (67.35 µg/ml of OTA. The maximum amount of germination was observed in control (without OTA treatment and at low concentration (13.80 µg/ml within 4 days. Antioxidant enzymes catalase and peroxidase decreased in germinated grains treated with OTA. Catalase was 18.12 U/ml in grains treated with low concentration (13.80 µg/ml of OTA while at high concentration (67.35 µg/ml, it was 12.23 U/ml compared with the control (20.33 U/ml. On the other hand, peroxidase decreased only in germinated grains treated with high concentration of OTA. The ultrastructural studies indicate that there were dramatic differences between the cells of root system of wheat seedlings of grains treated and untreated with the OTA. Cell ultrastructures of treated grains with OTA showed that the cytoplasmic membrane collapses away from the cell wall. Plasmodesmata threads were appeared in untreated cells but not formed in treated cells.

  11. External costs related to power production technologies. ExternE national implementation for Denmark

    Energy Technology Data Exchange (ETDEWEB)

    Schleisner, L.; Sieverts Nielsen, P. [eds.

    1997-12-01

    The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results, to aggregate these site- and technology-specific results to more general figures. The current report covers the detailed information concerning the ExternE methodology. Importance is attached to the computer system used in the project and the assessment of air pollution effects on health, materials and ecological effects. Also the assessment of global warming damages are described. Finally the report covers the detailed information concerning the national implementation for Denmark for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant base on biogas. (au) EU-JOULE 3. 79 tabs., 11 ills., 201 refs.

  12. Seed germination strategies: an evolutionary trajectory independent of vegetative functional traits

    Directory of Open Access Journals (Sweden)

    Gemma eHoyle

    2015-10-01

    Full Text Available 1.Seed germination strategies vary dramatically among species but relatively little is known about how germination traits correlate with other elements of plant strategy systems. Understanding drivers of germination strategy is critical to our understanding of the evolutionary biology of plant reproduction.2.We present a novel assessment of seed germination strategies focussing on Australian alpine species as a case study. We describe the distribution of germination strategies and ask whether these are correlated with, or form an independent axis to, other plant functional traits. Our approach to describing germination strategy mimicked realistic temperatures that seeds experience in situ following dispersal. Strategies were subsequently assigned using an objective clustering approach. We hypothesised that two main strategies would emerge, involving dormant or non-dormant seeds, and that while these strategies would be correlated with seed traits (e.g. mass or endospermy they would be largely independent of vegetative traits when analysed in a phylogenetically structured manner. 3.Across all species, three germination strategies emerged. The majority of species postponed germination until after a period of cold, winter-like temperatures indicating physiological and/or morphological dormancy mechanisms. Other species exhibited immediate germination at temperatures representative of those at dispersal. Interestingly, seeds of an additional 13 species 'staggered' germination over time. Germination strategies were generally conserved within families. Across a broad range of ecological traits only seed mass and endospermy showed any correlation with germination strategy when phylogenetic relatedness was accounted for; vegetative traits showed no significant correlations with germination strategy. The results indicate that germination traits correlate with other aspects of seed ecology but form an independent axis relative to vegetative traits.

  13. Externality and burnout among dentists.

    Science.gov (United States)

    St-Yves, A; Freeston, M H; Godbout, F; Poulin, L; St-Amand, C; Verret, M

    1989-12-01

    This study investigates the relationship between burnout as measured by the Maslach Burnout Inventory and locus of control as measured by the Adult Nowicki-Strickland Internal-External Locus of Control (ANS-IE) for 82 dentists. Significant Pearson correlations between two Maslach subscales and locus of control show Personal Accomplishment to be negatively associated -.31 and Emotional Exhaustion to be positively correlated .21 to externality.

  14. Relatie interne en externe audit

    OpenAIRE

    Ghys, Emelie

    2011-01-01

    In het eerste hoofdstuk wordt de probleemstelling van deze eindverhandeling besproken. Interne en externe audit worden de laatste jaren internationaal en nationaal meer en meer erkend in het bedrijfsleven. Aanleiding voor de toenemende belangstelling van de interne en externe auditfunctie zijn de verschillende boekhoudschandalen rond corporate governance of deugdelijk bestuur. Deze financiële mislukkingen leidden wereldwijd tot diverse wetten, nieuwe regels en verbeterde standaarden om zo een...

  15. Performance Targets and External Benchmarking

    DEFF Research Database (Denmark)

    Friis, Ivar; Hansen, Allan; Vámosi, Tamás S.

    as a market mechanism that can be brought inside the firm to provide incentives for continuous improvement and the development of competitive advances. However, whereas extant research primarily has focused on the importance and effects of using external benchmarks, less attention has been directed towards...... towards the conditions for the use of the external benchmarks we provide more insights to some of the issues and challenges that are related to using this mechanism for performance management and advance competitiveness in organizations....

  16. Parallel External Memory Graph Algorithms

    DEFF Research Database (Denmark)

    Arge, Lars Allan; Goodrich, Michael T.; Sitchinava, Nodari

    2010-01-01

    In this paper, we study parallel I/O efficient graph algorithms in the Parallel External Memory (PEM) model, one o f the private-cache chip multiprocessor (CMP) models. We study the fundamental problem of list ranking which leads to efficient solutions to problems on trees, such as computing lowest...... an optimal speedup of ¿(P) in parallel I/O complexity and parallel computation time, compared to the single-processor external memory counterparts....

  17. Drying characteristics of germinated brown rice%发芽糙米的干燥特性研究

    Institute of Scientific and Technical Information of China (English)

    贾富国; 韩珊; 曹银平; 姜鹏

    2013-01-01

    The influence of drying conditions ,in terms of drying temperature,air velocity and relative humidity,on the change trends moisture content of germinated brown rice was studied in a thin-drying experimental table.The experimental data was analyzed with software of Matlab and Excel. A mathematical model was developed to describe the thin-layer drying of germinated brown rice. The results showed that drying temperature and air velocity have obviously influence on the moisture content of germinated brown, and the relative humidity of air has the least effect. The model could illustrate and predict the changing pattern of germinated brown rice moisture under drying conditions,with correlation of 0.9854. The results provided a theoretical basis for the predication of moisture content change of germinated brown rice.%  为探讨干燥条件对发芽糙米含水率变化的影响,应用薄层干燥试验台,研究干燥温度、表现风速以及相对湿度对发芽糙米含水率变化的影响.利用Matlab软件和Excel软件处理试验数据,建立了相关的薄层干燥数学模型.结果表明,干燥温度和表现风速对发芽糙米含水率变化影响显著,而相对湿度对其影响较小;依据试验数据建立的薄层干燥数学模型可以描述和预测发芽糙米干燥过程中水分的变化规律,其相关系数为0.9854.试验结果可以为研究发芽糙米干燥过程中水分变化规律提供理论依据.

  18. Proteomic analysis of lettuce seed germination and thermoinhibition by sampling of individual seeds at germination and removal of storage proteins by polyethylene glycol fractionation.

    Science.gov (United States)

    Wang, Wei-Qing; Song, Bin-Yan; Deng, Zhi-Jun; Wang, Yue; Liu, Shu-Jun; Møller, Ian Max; Song, Song-Quan

    2015-04-01

    Germination and thermoinhibition in lettuce (Lactuca sativa 'Jianyexianfeng No. 1') seeds were investigated by a proteomic comparison among dry seeds, germinated seeds at 15°C, at 15°C after imbibition at 25°C for 48 h, or at 25°C in KNO3 (all sampled individually at germination), and ungerminated seeds at 25°C, a thermoinhibitory temperature. Before two-dimensional gel electrophoresis analysis, storage proteins (greater than 50% of total extractable protein) were removed by polyethylene glycol precipitation, which significantly improved the detection of less abundant proteins on two-dimensional gels. A total of 108 protein spots were identified to change more than 2-fold (Pgermination treatment. Nineteen proteins increasing and one protein decreasing in abundance during germination had higher abundance in germinated 15°C, 15°C after imbibition at 25°C for 48 h, and 25°C in KNO3 seeds than in ungerminated 25°C seeds. Gene expression of 12 of those proteins correlated well with the protein accumulation. Methionine metabolism, ethylene production, lipid mobilization, cell elongation, and detoxification of aldehydes were revealed to be potentially related to lettuce seed germination and thermoinhibition. Accumulation of three proteins and expression of five genes participating in the mevalonate (MVA) pathway of isoprenoid biosynthesis correlated positively with seed germinability. Inhibition of this pathway by lovastatin delayed seed germination and increased the sensitivity of germination to abscisic acid. MVA pathway-derived products, cytokinins, partially reversed the lovastatin inhibition of germination and released seed thermoinhibition at 25°C. We conclude that the MVA pathway for isoprenoid biosynthesis is involved in lettuce seed germination and thermoinhibition.

  19. A Gompertz regression model for fern spores germination

    Directory of Open Access Journals (Sweden)

    Gabriel y Galán, Jose María

    2015-06-01

    Full Text Available Germination is one of the most important biological processes for both seed and spore plants, also for fungi. At present, mathematical models of germination have been developed in fungi, bryophytes and several plant species. However, ferns are the only group whose germination has never been modelled. In this work we develop a regression model of the germination of fern spores. We have found that for Blechnum serrulatum, Blechnum yungense, Cheilanthes pilosa, Niphidium macbridei and Polypodium feuillei species the Gompertz growth model describe satisfactorily cumulative germination. An important result is that regression parameters are independent of fern species and the model is not affected by intraspecific variation. Our results show that the Gompertz curve represents a general germination model for all the non-green spore leptosporangiate ferns, including in the paper a discussion about the physiological and ecological meaning of the model.La germinación es uno de los procesos biológicos más relevantes tanto para las plantas con esporas, como para las plantas con semillas y los hongos. Hasta el momento, se han desarrollado modelos de germinación para hongos, briofitos y diversas especies de espermatófitos. Los helechos son el único grupo de plantas cuya germinación nunca ha sido modelizada. En este trabajo se desarrolla un modelo de regresión para explicar la germinación de las esporas de helechos. Observamos que para las especies Blechnum serrulatum, Blechnum yungense, Cheilanthes pilosa, Niphidium macbridei y Polypodium feuillei el modelo de crecimiento de Gompertz describe satisfactoriamente la germinación acumulativa. Un importante resultado es que los parámetros de la regresión son independientes de la especie y que el modelo no está afectado por variación intraespecífica. Por lo tanto, los resultados del trabajo muestran que la curva de Gompertz puede representar un modelo general para todos los helechos leptosporangiados

  20. Germination of radish seeds (Raphanus sativus treated with homeopathic drugs

    Directory of Open Access Journals (Sweden)

    Solange Monteiro de Toledo Piza Gomes Carneiro

    2011-09-01

    Full Text Available The radish is a short cycle crop, since it is harvested at 25-30 days after direct sowing. Under the economic point of view it is an important species, but there are few studies on germination of radish seeds. The objective of this study was to evaluate the effect of high diluted substances on the germination of radish seeds. The trial was conducted at the Agricultural Research Institute of Paraná (IAPAR in Londrina / Paraná. It was used a pesticide free cultivar named Cometa. The treatments were: Bryonia, hydroalcoholic solution, Arnica montana, Cina and Lupine + Oat, all of them diluted and agitated at 9x; distilled water and agitated distilled water were used as controls. The mother tincture of Lupine + Oat was prepared from plants collected at the experimental station of IAPAR in Londrina. The mother tincture and all treatments were prepared according to the guidelines in the Brazilian Homeopathic Pharmacopeia, Part I [1]. The agitations of the treatments were made by a mechanical equipment, model Denise 10-50 manufactured by Autic. The water was distilled the day before preparing the treatments. The experiment was performed with 300 seeds per treatment. The seeds were placed in gerbox with germitest paper, and 50 gerbox were used per treatment, with six seeds in each gerbox. The germitest papers were moistened with the treatments and the seeds were soaked for 2 hours previously set up the experiment. The substances in high dilutions were agitated 100 times on the machine before soaking the seeds and moistening the germitest paper. The experimental design was entirely randomized and the gerbox were kept at the bench at the Laboratory of Plant Protection of IAPAR. A person not involved in conduct of the experiment coded (blinded the treatments solutions with a random letter code. The code was kept secret until all measurements and data processing were finished. Seeds were observed daily for germination and counted only those

  1. External Costs Related to Power Production Technologies

    DEFF Research Database (Denmark)

    Ibsen, Liselotte Schleisner; Nielsen, Per Sieverts

    1997-01-01

    The European Commission has launched a major study project, ExternE, to develop a methodology to quantify externalities. A “National Implementation Phase”, was started under the Joule II programme with the purpose of implementing the ExternE methodology in all member states. The main objective...

  2. External Costs Related to Power Production Technologies

    DEFF Research Database (Denmark)

    Ibsen, Liselotte Schleisner; Nielsen, Per Sieverts

    1997-01-01

    The European Commission has launched a major study project, ExternE, to develop a methodology to quantify externalities. A “National Implementation Phase”, was started under the Joule II programme with the purpose of implementing the ExternE methodology in all member states. The main objective of...

  3. The allelopathic effect of Taraxacum officinale F.G. Wigg on the seeds germination and initial growth of Lolium westerwoldicum R.Br.

    Directory of Open Access Journals (Sweden)

    Jolanta Jankowska

    2012-12-01

    Full Text Available The common dandelion (Taraxacum officinale F.H. Wigg is a perennial plant often found in large concentrations in the sward of natural meadows. This species expands quickly, displacing other species. In literature there is a lack of data relating to the effect of common dandelion on plants growing in its vicinity. It is also not known why this species creates large clusters. Perhaps it competes with different plants through the allelopathic effect. Hence, the aim of this study was to determine the influence of water extracts from leaves and roots of common dandelion (Taraxacum officinale as well as soil extracts from the root layer of this species on seed germination and the initial growth of Lolium westerwoldicum R.Br. The investigated material comprised leaves and roots of Taraxacum officinale. The germination biotest most often used in experiments was applied. The seeds germination energy of westerwolds ryegrass was most inhibited by plant extracts prepared from roots and leaves of Taraxacum officinale. The germination ability of seeds of Lolium westerwoldicum was the highest in the treatments in which soil extracts were applied; however, the value of this feature was limited to a larger extent by the plant extracts from leaves of Taraxacum officinale than from roots. Higher concentrations of both soil and plant solutions had an inhibitory effect both on root growth and the growth of the leaf sheath and leaves of westerwolds ryegrass. The results of the tested parameters can confirm the allelopathic effect of Taraxacum officinale on germination and initial growth of Lolium westerwoldicum, and especially that of extracts prepared from leaves.

  4. An effective nutrient medium for asymbiotic seed germination and large-scale in vitro regeneration of Dendrobium hookerianum, a threatened orchid of northeast India

    Science.gov (United States)

    Paul, Sumi; Kumaria, Suman; Tandon, Pramod

    2012-01-01

    Background and aims Dendrobium hookerianum is a rare and threatened epiphytic orchid of northeast India. Prospects for conservation would be strengthened by developing an in vitro method for mass propagation. Seeds are minute and difficult to use directly in the field for this purpose, being non-endospermous with a low nutrient content and dependent on a specific fungus for germination and early seedling development. Although produced in large numbers (2–3 million per capsule), develop a rapid and successful method for in vitro propagation based on an initial in vitro asymbiotic seed germination step that achieved high percentages. Methodology Effects of four different media, i.e. (i) Murashige and Skoog (MS), (ii) Mitra et al., (iii) Knudson (KC) and (iv) Gamborg et al. (B5), were evaluated for large-scale multiplication by asymbiotic seed germination. Seedling leaf number, shoot number, shoot length, root number and root length were scored. After 7–8 months, large numbers of well-rooted plantlets were transferred to a glasshouse in thermocol pots containing compost. Six different composts based on broken brick and charcoal were compared for their ability to support further development over 90 days of hardening. Principal results The fastest and highest percentage seed germination was achieved using MS medium. Seeds on MS medium germinated in 3–4 weeks compared with 7–8 weeks on B5 medium. Seedling development was also superior on MS medium. The inclusion of plant growth regulators was unnecessary. Compost comprising broken brick and charcoal with an upper layer of moss was found to be the most suitable for the survival of transferred plantlets. Ninety per cent survival of plantlets was achieved 90 days after transfer to a glasshouse. Conclusions The use of MS culture medium is well suited for the mass multiplication of D. hookerianum plants intended for re-introducing this threatened orchid into the wild.

  5. Proliferation of granulosa and thecal cells in germinal disc and non-disc regions during follicular growth in Japanese quail (Coturnix coturnix japonica): bromodeoxyuridine incorporation in situ.

    Science.gov (United States)

    Yoshimura, Y; Okamoto, T; Tamura, T

    1996-05-01

    Proliferation of granulosa and thecal cells was analysed during ovarian follicular growth in laying Japanese quail. The birds were injected intraperitoneally with bromodeoxyuridine (BrdU) 10 or 4 h before ovulation, that is, before or after a preovulatory LH surge, respectively, and incorporation of BrdU by follicular tissues was detected immunocytochemically. Cells labelled with BrdU were seldom seen in the most immature follicles in the ovarian cortex, whereas many granulosa and thecal cells were labelled with BrdU in medium-sized white yolky follicles (approximately 13.3% and 14.4% in granulosa and theca layers, respectively). Ten and four hours before ovulation, the granulosa cells in the germinal disc and non-disc regions of the third largest yellow yolky follicle (F3) were labelled with BrdU (approximately 8.4% and 9.4% in germinal disc; 6.1% and 9.0% in the non-disc region), but only those in the germinal disc region were labelled (approximately 5.4% and 4.0%) in the largest yellow yolky follicle (F1). The percentage of thecal cells labelled with BrdU 4 h before ovulation was significantly higher than the percentage labelled 10 h before ovulation, and was higher in F3 (approximately 11.7%) than in F1 follicles (approximately 5.4%) 4 h before ovulation. These results show that proliferation of granulosa and thecal cells occurs in both germinal disc and non-disc regions in growing follicles, but when a follicle matures proliferation is reduced and in the case of granulosa cells it is restricted to the germinal disc region.

  6. Germination Response of MR 219 Rice Variety to Different Exposure Times and Periods of 2450 MHz Microwave Frequency

    OpenAIRE

    Daryush Talei; Alireza Valdiani; Mahmood Maziah; Mohammad Mohsenkhah

    2013-01-01

    Germination is a key process in plants' phenological cycles. Accelerating this process could lead to improvment of the seedling growth as well as the cultivation efficiency. To achieve this, the effect of microwave frequency on the germination of rice seeds was examined. The physiological feedbacks of the MR 219 rice variety in terms of seed germination rate (GR), germination percentage (GP), and mean germination time (MGT) were analyzed by exposing its seeds to 2450 MHz of microwave frequenc...

  7. Dormancy of the barley grain is correlated with gibberellic Acid responsiveness of the isolated aleurone layer.

    Science.gov (United States)

    Schuurink, R C; Sedee, N J; Wang, M

    1992-12-01

    The relationship between barley grain dormancy and gibberellic acid (GA(3)) responsiveness of aleurone layers has been investigated. Barley (Hordeum distichum L. cvs Triumph and Kristina) grains were matured under defined conditions in a phytotron. Grains of Triumph plants grown under long-day/warm conditions had lower dormancy levels than grains of plants grown under short-day/cool conditions. Aleurone layers isolated from grains of long-day Triumph plants secreted more alpha-amylase and had a higher responsiveness to GA(3) as measured by alpha-amylase secretion. Storage of the grains increased both the percentage of germination and the responsiveness of the aleurone to GA(3). Use of different sterilization methods to break dormancy confirmed the correlation between germination percentage and aleurone layer GA(3) responsiveness. The response of embryoless Triumph grains to GA(3) was lower than that of the isolated aleurone layers, suggesting a role of the starchy endosperm in regulating the GA(3) response of the aleurone layer. Grains of the cultivar Kristina harvested from short day- and long day-grown plants lacked dormancy, and their isolated aleurone layers had a similar responsiveness to GA(3) as measured by alpha-amylase secretion. The data indicate that the physiological state of the aleurone layers contributes to the percentage germination of the grains.

  8. Transcriptional regulatory programs underlying barley germination and regulatory functions of Gibberellin and abscisic acid

    Directory of Open Access Journals (Sweden)

    Lin Li

    2011-06-01

    Full Text Available Abstract Background Seed germination is a complex multi-stage developmental process, and mainly accomplished through concerted activities of many gene products and biological pathways that are often subjected to strict developmental regulation. Gibberellins (GA and abscisic acid (ABA are two key phytohormones regulating seed germination and seedling growth. However, transcriptional regulatory networks underlying seed germination and its associated biological pathways are largely unknown. Results The studies examined transcriptomes of barley representing six distinct and well characterized germination stages and revealed that the transcriptional regulatory program underlying barley germination was composed of early, late, and post-germination phases. Each phase was accompanied with transcriptional up-regulation of distinct biological pathways. Cell wall synthesis and regulatory components including transcription factors, signaling and post-translational modification components were specifically and transiently up-regulated in early germination phase while histone families and many metabolic pathways were up-regulated in late germination phase. Photosynthesis and seed reserve mobilization pathways were up-regulated in post-germination phase. However, stress related pathways and seed storage proteins were suppressed through the entire course of germination. A set of genes were transiently up-regulated within three hours of imbibition, and might play roles in initiating biological pathways involved in seed germination. However, highly abundant transcripts in dry barley and Arabidopsis seeds were significantly conserved. Comparison with transcriptomes of barley aleurone in response to GA and ABA identified three sets of germination responsive genes that were regulated coordinately by GA, antagonistically by ABA, and coordinately by GA but antagonistically by ABA. Major CHO metabolism, cell wall degradation and protein degradation pathways were up

  9. An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination.

    Directory of Open Access Journals (Sweden)

    Julien De Giorgi

    2015-12-01

    Full Text Available Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA and abscisic acid (ABA signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties.

  10. An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination.

    Science.gov (United States)

    De Giorgi, Julien; Piskurewicz, Urszula; Loubery, Sylvain; Utz-Pugin, Anne; Bailly, Christophe; Mène-Saffrané, Laurent; Lopez-Molina, Luis

    2015-12-01

    Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA) and abscisic acid (ABA) signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties.

  11. An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination

    Science.gov (United States)

    Loubery, Sylvain; Utz-Pugin, Anne; Bailly, Christophe; Mène-Saffrané, Laurent; Lopez-Molina, Luis

    2015-01-01

    Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA) and abscisic acid (ABA) signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties. PMID:26681322

  12. Successful external fertilization in turbulent environments.

    Science.gov (United States)

    Serrao, E A; Pearson, G; Kautsky, L; Brawley, S H

    1996-05-28

    Mathematical and experimental simulations predict that external fertilization is unsuccessful in habitats characterized by high water motion. A key assumption of such predictions is that gametes are released in hydrodynamic regimes that quickly dilute gametes. We used fucoid seaweeds to examine whether marine organisms in intertidal and subtidal habitats might achieve high levels of fertilization by restricting their release of gametes to calm intervals. Fucus vesiculosus L. (Baltic Sea) released high numbers of gametes only when maximal water velocities were below ca. 0.2 m/s immediately prior to natural periods of release, which occur in early evening in association with lunar cues. Natural fertilization success measured at two sites was always close to 100%. Laboratory experiments confirmed that (i) high water motion inhibits gamete release by F. vesiculosus and by the intertidal fucoids Fucus distichus L. (Maine) and Pelvetia fastigiata (J. Ag.) DeToni (California), and (ii) showed that photosynthesis is required for high gamete release. These data suggest that chemical changes in the boundary layer surrounding adults during photosynthesis and/or mechanosensitive channels may modulate gamete release in response to changing hydrodynamic conditions. Therefore, sensitivity to environmental factors can lead to successful external fertilization, even for species living in turbulent habitats.

  13. The SNS External Antenna H- Ion Source

    Energy Technology Data Exchange (ETDEWEB)

    Welton, Robert F [ORNL; Stockli, Martin P [ORNL; Murray Jr, S N [ORNL; Crisp, Danny W [ORNL; Carmichael, Justin R [ORNL; Goulding, Richard Howell [ORNL; Han, Baoxi [ORNL; Pennisi, Terry R [ORNL; Santana, Manuel [ORNL

    2010-01-01

    The U.S. Spallation Neutron Source (SNS) is an accelerator-based, pulsed neutron-scattering facility, currently in the process of ramping up neutron production. In order to insure that we will meet our operational commitments as well as provide for future facility upgrades with high reliability, we have developed an RF-driven, H- ion source based on a ceramic aluminum nitride (AlN) plasma chamber [1]. This source is expected to be utilized by the SNS for neutron production starting in 2009. This report details the design of the production source which features an AlN plasma chamber, 2-layer external antenna, cooled-multicusp magnet array, Cs2CrO4 cesium system and a Molybdenum plasma ignition gun. Performance of the production source both on the SNS accelerator and SNS test stand is reported. The source has also been designed to accommodate an elemental Cs system with an external reservoir which has demonstrated unanalyzed beam currents up to ~100mA (60Hz, 1ms) on the SNS ion source test stand.

  14. Can heavy metal pollution defend seed germination against heat stress? Effect of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination under high temperature.

    Science.gov (United States)

    Deng, Benliang; Yang, Kejun; Zhang, Yifei; Li, Zuotong

    2016-09-01

    Heavy metal pollution, as well as greenhouse effect, has become a serious threat today. Both heavy metal and heat stresses can arrest seed germination. What response can be expected for seed germination under both stress conditions? Here, the effects of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination were investigated at 20 °C and 40 °C. Compared with 20 °C, heat stress induced thermodormancy. However, this thermodormancy could be significantly alleviated by the addition of a low concentration of heavy metals. Heavy metals, as well as heat stress induced H2O2 accumulation in germinating seeds. Interestingly, this low concentration of heavy metal that promoted seed germination could be partly blocked by DMTU (a specific ROS scavenger), irrespective of temperature. Accordingly, H2O2 addition reinforced this promoting effect on seed germination, which was induced by a low concentration of heavy metal. Furthermore, we found that the NADPH oxidase derived ROS was required for seed germination promoted by the heavy metals. Subsequently, treatment of seeds with fluridone (a specific inhibitor of ABA) or ABA significantly alleviated or aggravated thermodormancy, respectively. However, this alleviation or aggravation could be partly attenuated by a low concentration of heavy metals. In addition, germination that was inhibited by high concentrations of heavy metals was also partly reversed by fluridone. The obtained results support the idea that heavy metal-mediated ROS and hormone interaction can finally affect the thermodormancy release or not.

  15. Alicyclobacillus acidoterrestris: new methods for inhibiting spore germination.

    Science.gov (United States)

    Bevilacqua, A; Sinigaglia, M; Corbo, M R

    2008-07-15

    For a long period the thermal processing has been considered as the only way to reduce the initial spore number of Alicyclobacillus acidoterrestris and prevent the spoilage of acidic beverage. New methods, however, were proposed by the literature to control spore germination both in laboratory media and in real systems. After a brief introduction on the impact of A. acidoterrestris in food microbiology and a description of enumeration methods and heat processing applied by the juices manufactures, a review of innovative approaches to inhibit and/or control spore germination is proposed. In particular, this paper focuses on two different topics; the 1st is the use of some natural compounds (monolaurin, lysozyme, nisin and essential oils) or some chemicals, conventional (like sodium-benzoate, organic acids, surfactants and chlorine dioxide) or not conventional (chlorine dioxide as gas). The 2nd topic is a description of some innovative methods to reduce the initial spore number (high hydrostatic and homogenisation pressures, radiation and microwaves).

  16. Effect of seed stimulation on germination and sugar beet yield

    Science.gov (United States)

    Prośba-Białczyk, U.; Szajsner, H.; Grzyś, E.; Demczuk, A.; Sacała, E.; Bąk, K.

    2013-03-01

    Germination and sugar beet yield after seed stimulation were investigated. The seeds came from the energ'hill technology and were subject to laser irradiation. The experiments were conducted in the laboratory and field conditions. Lengthening of germinal roots and hypocotyls was observed. A positive effect of the stimulation on the morphological features was observed for the Eh seeds and laser irradiation applied in a three-fold dose. The energ'hill seeds exhibited a significantly higher content of carotenoids in seedlings and an increase in the content of chlorophylls. Laser light irradiation favourably modified the ratio of chlorophyll a to b. The leaves and roots of plants developed from the energ'hill and irradiated seeds were characterized by higher dry matter content thanin non-stimulated seeds. Seed stimulation had a positive influence on yielding and the saccharose content.

  17. Proteomics and posttranslational proteomics of seed dormancy and germination.

    Science.gov (United States)

    Rajjou, Loïc; Belghazi, Maya; Catusse, Julie; Ogé, Laurent; Arc, Erwann; Godin, Béatrice; Chibani, Kamel; Ali-Rachidi, Sonia; Collet, Boris; Grappin, Philippe; Jullien, Marc; Gallardo, Karine; Job, Claudette; Job, Dominique

    2011-01-01

    The seed is the dispersal unit of plants and must survive the vagaries of the environment. It is the object of intense genetic and genomic studies because processes related to seed quality affect crop yield and the seed itself provides food for humans and animals. Presently, the general aim of postgenomics analyses is to understand the complex biochemical and molecular processes underlying seed quality, longevity, dormancy, and vigor. Due to advances in functional genomics, the recent past years have seen a tremendous progress in our understanding of several aspects of seed development and germination. Here, we describe the proteomics protocols (from protein extraction to mass spectrometry) that can be used to investigate several aspects of seed physiology, including germination and its hormonal regulation, dormancy release, and seed longevity. These techniques can be applied to the study of both model plants (such as Arabidopsis) and crops.

  18. Pollen germination and pollen tube growth in ZP maize lines

    Directory of Open Access Journals (Sweden)

    Cerović Radosav

    2014-01-01

    Full Text Available The study was conducted on the in vitro pollen germination at 26°, 28°, 32° and 35°C for 24h of male parental lines, pollen tube growth in vivo in cross pollination of female and male parental lines that make couples in four hybrids: ZP 504 su (♀ ZPPL 51 × ♂ ZPPL 67; ZP 677 (♀ ZPPL 17 × ♂ ZPPL 201; ZP 704 (♀ ZPPL 109 × ♂ ZPPL 79, ZP 611 k (♀ ZPPL 126 × ♂ ZPPL 105, and the open pollination of female parental lines of the above mentioned hybrids. Pollen germination in vitro and pollen tube growth dynamics in vivo showed different genotypic specificities with the tests applied. The obtained results were discussed in the context of reproductive biology of ZP maize lines and aimed to create the preconditions for successful management and direction of the process in practice - seed production in certain environmental conditions.

  19. Algebraic determination of the evolutionary stable germination fraction.

    Science.gov (United States)

    Valleriani, Angelo

    2005-11-01

    In this article, we consider a bet-hedging model with density dependence for germination behavior of dormant seeds. We show how to compute accurate values of the evolutionary stable germination fraction using a method based on expansion around the average seed bank size. The expansion is made up to the fourth order and is expressed in terms of the first four moments of the distribution of the year-to-year variation in the average yield per adult plant. This method leads to a simple algebraic equation, which can be solved without recurring to simulations of the seed bank dynamics. We first show the analytical derivation under general assumptions about the effect of density dependence. We then test our results with a numerical analysis where an explicit form of the density dependence has been taken.

  20. Effect of Magnetic Field on Seed Germination of Wheat

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    Hussein Falaihj HUSSEIN

    2012-12-01

    Full Text Available The current project studies the influence of the exposure rate of the magnetic field (50 mT/time upon germination in wheat seeds. Magnetic treatment involved the application of three different exposure rates (0.5, 1, 2 h respectively. The effect of the exposure rate on the root growth, radicle growth and protein percentage are discussed and statistical significance analysis is assessed for the differences between the average values of samples and controls. The variable magnetic field of exposure rate (50 mT/0.5h is a very significant factor in influencing the germination process of wheat seeds. It is observed that the root length, radicle length and the protein percentage increase up to 10, 14 and 8 % respectively.

  1. [Characteristics of seed germination of rare plant species Reaumuria trigyna in west Ordos].

    Science.gov (United States)

    Zhang, Ying-juan; Wang, Yu-shan; Li, Qing-feng

    2008-12-01

    Reaumuria trigyna is a relic species in the desert shrubbery vegetation in arid regions of northwestern China, and plays an important role in the maintenance of the stability of desert vegetation. In this paper, the seed traits and germination strategy of R. trigyna under different environmental conditions, e.g., light, temperature, soil moisture, and sand bury, were investigated. The results showed that R. trigyna seed had high vigor and high germination rate, and endured reserve. The seed could germinate either in light or in darkness, and the optimal temperature for germination was 20 degrees C - 25 degrees C or 15 degrees C/25 degrees C, with the germination rate being 93%. The seed could start to germinate when soil moisture content was 2%, and the germination rate was the highest (89%) when the moisture content was 12%. The optimal sand burial depth of R. trigyna seed was 1 cm, and no seed would germinate when the sand burial depth was >5 cm. Sand burial depth had significant effects on the seedling's emergence percentage and growth height, but lesser effects on seedling' s mass. Soil moisture and sand burial depth were the main environmental factors limiting the seed germination and seedling emergence of R. trigyna. The high seed germination rate of R. trigyna enhanced the survival risk of its seedlings, which was unfavorable to its handling with the extreme changes of desert environment. Such a character of R. trigyna seed was one of the factors causing the species endangered.

  2. Seed germination of three species of Fabaceae typical of seasonally dry forest

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    Daniel Meira Arruda

    2015-06-01

    Full Text Available This study evaluates seeds germination of Anadenanthera colubrina, Acacia polyphylla and Bauhinia cheilantha, typical species of deciduous forests. Seeds were submitted to pre-germination treatments and attack of native insects. The seeds of each species were grouped in: seeds scarified with sandpaper; seeds immersed in water heated to 70 °C, seeds with signs of attack by herbivore insects and the control group. The largest proportion of germinated seeds occurred in the first week of incubation and germination peak, ranged from first to third day. All groups of A. polyphylla and B.cheilantha showed high germination rate (> 90%, being reduced only when seeds were attacked by insects (< 25%. Mechanic scarification was efficient in A. polyphylla by enhancing germination to maximum (100% and accelerating germination. A. colubrina showed no difference among groups, and germination rate was lower (< 50%, which was attributed to infestation by fungi, commonly reported in this species and apparently independent of usual hygiene procedures. Finally, except the fungi infestation in A. colubrina, evaluated species were independent of pre-germination treatment to obtain a high rate of germination.

  3. Are cactus growth forms related to germination responses to light? A test using Echinopsis species

    Science.gov (United States)

    Ortega-Baes, Pablo; Aparicio-González, Mónica; Galíndez, Guadalupe; del Fueyo, Patricia; Sühring, Silvia; Rojas-Aréchiga, Mariana

    2010-05-01

    In this study, we investigated the effect of light regimen (white light vs. darkness) on the germination of 12 species of the Echinopsis genus (tribe Trichocereeae, Cactaceae). This genus presents a variety of growth forms and relatively small and uniform seed size. These traits allowed us to test, within the same linage and removing seed mass effect, the hypothesis that the germination response to light (indifferent to light or positive photoblastic) is related to growth form. Our results reject this hypothesis since no seeds germinated in darkness, so all of the species can be classified as being positively photoblastic. The proportion of seed germination with white light was significantly different among cactus growth forms. Columnar cacti (arborescent, creeping and short) showed a greater proportion of seed germination than barrel and globose cacti. The germination rate differed among growth forms and species. At constant temperatures, creeping columnar cacti presented a significantly higher germination rate than the other growth forms. With alternating temperatures, columnar cacti showed higher germination rates than the other growth forms. The low proportion of seeds that germinated for some species indicates that they show seed dormancy. Our results suggest that germination responses to light in the cactus family could be related to seed mass and phylogenetic constraints.

  4. Seed germination in response to chemicals: effect of nitrogen and pH in the media.

    Science.gov (United States)

    Pérez-Fernández, M A; Calvo-Magro, E; Montanero-Fernández, J; Oyola-Velasco, J A

    2006-01-01

    Seed germination generally presents a peak in the next growing season after a fire. Among other factors associated with fire are the increase of soil nitrogen and changes in the pH of the soil. In this study, we addressed the question, whether or not the germination response of eight species is linked with the increase in pH and nitrogenous compounds in the germination media? We assessed the separate and combined effects of nitrogenous compounds and pH on the percentage and rate of germination of seeds of Medicago arabica (L.) Hudson, Epilobium hirsutum L., Foeniculum vulgare Miller, Daucus carota L., Thapsia villosa L., Cynosurus cristatus L., Dactylis glomerata L. and Rumex crispus L. All these species are well represented in the Mediterranean ecosystems of the central-west Spain. Water and CaCl2 were used as controls. Nitrogenous compounds increased percent germination (level) and rate in three of the species studied. High pH negatively affected the germination rate of seeds from most species, but had no effect on the per cent germination of any of the species. The higher concentration of the nutritious solutions affected negatively the germination level and rate. The different germination responses of seeds of the studied species could not be exclusively attributed to pH values in the media, whereas the amount and form of Nitrogen in the media has a greater effect on it. These differences in germination are species dependent.

  5. [Studies on biological characteristics and germination conditions of Thladiantha dubia seeds].

    Science.gov (United States)

    Zhao, Chun-Ying; Su, Zhan-Hui; Mao, Xiao-Xia; Tong, Ji-Ming

    2013-07-01

    To study the biological characteristics and find out the optimum condition for germination of seed of Thladiantha dubia Bunge for its standardized culturing. The weight per 1 000 seeds, seed moisture content and seed viability were determined. The biological characteristics were studied and germination conditions of seed of T. dubia were tested under following conditions: different seed soaking time, different temperatures (15, 20, 25, 30, 35 degrees C) and different irradiation time (0, 5, 10, 15, 20 min). The average length, width and thickness of T. Dubia seed were 4.96, 3.25 and 1.08 mm, respectively. The weight per 1 000 seeds was 14.03 g; the seed moisture content was 10.10%; the seed viability was 90.33%. Under the same condition of light, temperature and other factors, the seed germination percentage and germination energy were the highest after seed soaking 24 h. The suitable temperature range of seeds was form 25 degrees C to 35 degrees C. Under different irradiation time, the seed germination percentage and germination energy were the highest after irradiation 10 min. In different germinating beds, the seeds germination percentage and germination energy were the highest on paper (TP), which was 89.33%. The optimum condition for the germination of the seed of T. dubia is seed soaking 12 h, irradiation 10 min, 25-30 degrees C on filter paper.

  6. Structural requirements of strigolactones for germination induction and inhibition of Striga gesnerioides seeds.

    Science.gov (United States)

    Nomura, Saki; Nakashima, Hitomi; Mizutani, Masaharu; Takikawa, Hirosato; Sugimoto, Yukihiro

    2013-06-01

    Structure-activity relationship studies of strigolactones and Striga gesnerioides seed germination revealed strict structural requirements for germination induction and a new function of the plant hormones as germination inhibitors. Stereoisomers of the naturally occurring strigolactones, strigol, sorgolactone, orobanchol, sorgomol and 5-deoxystrigol, 36 in total, were prepared and screened for the ability to induce and/or inhibit the germination of Striga hermonthica and Striga gesnerioides seeds collected from mature plants that parasitized on sorghum and cowpea, respectively. All of the compounds induced S. hermonthica seed germination, albeit displayed differential activities. On the other hand, only a limited number of the compounds induced significant germination in S. gesnerioides, thus indicating strict structural requirements. Strigolactones inducing high germination in S. gesnerioides induced low germination in S. hermonthica. Strigolactones with the same configuration at C3a, C8b and C2' as that in 5-deoxystrigol (9a) induced high germination of S. hermonthica seeds, but most of them inhibited the germination of S. gesnerioides. The differential response of S. gesnerioides to strigolactones may play an important role in the survival of the species. However, the compounds could be used as means of control if mixed cropping of cowpea and sorghum is adopted.

  7. Control of macaw palm seed germination by the gibberellin/abscisic acid balance.

    Science.gov (United States)

    Bicalho, E M; Pintó-Marijuan, M; Morales, M; Müller, M; Munné-Bosch, S; Garcia, Q S

    2015-09-01

    The hormonal mechanisms involved in palm seed germination are not fully understood. To better understand how germination is regulated in Arecaceae, we used macaw palm (Acrocomia aculeata (Jacq.) Lodd. Ex Mart.) seed as a model. Endogenous hormone concentrations, tocopherol and tocotrienol and lipid peroxidation during germination were studied separately in the embryo and endosperm. Evaluations were performed in dry (D), imbibed (I), germinated (G) and non-germinated (NG) seeds treated (+GA3 ) or not treated (control) with gibberellins (GA). With GA3 treatment, seeds germinated faster and to a higher percentage than control seeds. The +GA3 treatment increased total bioactive GA in the embryo during germination relative to the control. Abscisic acid (ABA) concentrations decreased gradually from D to G in both tissues. Embryos of G seeds had a lower ABA content than NG seeds in both treatments. The GA/ABA ratio in the embryo was significantly higher in G than NG seeds. The +GA3 treatment did not significantly affect the GA/ABA ratio in either treatment. Cytokinin content increased from dry to germinated seeds. Jasmonic acid (JA) increased and 1-aminocyclopropane-1-carboylic acid (ACC) decreased after imbibition. In addition, α-tocopherol and α-tocotrienol decreased, while lipid peroxidation increased in the embryo during germination. We conclude that germination in macaw palm seed involves reductions in ABA content and, consequently, increased GA/ABA in the embryo. Furthermore, the imbibition process generates oxidative stress (as observed by changes in vitamin E and MDA).

  8. Photoinhibition of germination in grass seed--implications for prairie revegetation.

    Science.gov (United States)

    Mollard, Federico P O; Naeth, M Anne

    2014-09-01

    Germination photoinhibition is not a recognized cause of revegetation failure; yet prolonged sunlight exposure can inhibit germination of several grass species. This research addressed susceptibility to photoinhibition of selected native grass species used to restore Canadian prairies, and reclamation treatments to alter environmental conditions in order to release seeds from photoinhibition. Under laboratory conditions effects of photoinhibition were tested on the ability of seeds to germinate at low water potential and effects of daily alternating temperatures and nitrates to break photoinhibition. Whether surficial mulch can release seeds from photoinhibition was assessed in a field experiment. Germination photoinhibition was evident in Festuca hallii and Koeleria macrantha seeds even under very low irradiances. The prolonged exposure to light decreased germination rates and ability of seeds to germinate at low water potentials. Daily fluctuating temperatures released a fraction of Bromus carinatus and Elymus trachycaulus seeds from photoinhibition yet did not improve F. hallii or K. macrantha germinability. Nitrates failed to break seed photoinhibition in all species tested. In the field experiment, mulched F. hallii seeds (covered with an erosion control blanket) showed a tenfold increase in germination percentages relative to seeds exposed to direct sunlight, indicating the facilitative effects of mulching on attenuation of the light environment. We conclude that germination photoinhibition as a cause of emergence failures in land reclamation where seed is broadcast or shallow seeded should be recognized and germination photoinhibition included in the decision making process to select revegetation seeding techniques.

  9. Reduced seed germination in Arabidopsis over-expressing SWI/SNF2 ATPase genes.

    Science.gov (United States)

    Leeggangers, Hendrika A C F; Folta, Adam; Muras, Aleksandra; Nap, Jan-Peter; Mlynarova, Ludmila

    2015-02-01

    In the life of flowering plants, seed germination is a critical step to ensure survival into the next generation. Generally the seed prior to germination has been in a dormant state with a low rate of metabolism. In the transition from a dormant seed to a germinating seed, various epigenetic mechanisms play a regulatory role. Here, we demonstrate that the over-expression of chromatin remodeling ATPase genes (AtCHR12 or AtCHR23) reduced the frequency of seed germination in Arabidopsis thaliana up to 30% relative to the wild-type seeds. On the other hand, single loss-of-function mutations of the two genes did not affect seed germination. The reduction of germination in over-expressing mutants was more pronounced in stress conditions (salt or high temperature), showing the impact of the environment. Reduced germinations upon over-expression coincided with increased transcript levels of seed maturation genes and with reduced degradation of their mRNAs stored in dry seeds. Our results indicate that repression of AtCHR12/23 gene expression in germinating wild-type Arabidopsis seeds is required for full germination. This establishes a functional link between chromatin modifiers and regulatory networks towards seed maturation and germination.

  10. Densities straw and luminosity conditions on seed germination on seed germination of Euhphorbia heterophyllaDensidades de palha e condições de luminosidade na germinação de sementes de Euhphorbia heterophylla

    Directory of Open Access Journals (Sweden)

    Hermeson dos Santos Vitorino

    2012-06-01

    Full Text Available It was studied the influence of sugarcane straw density and light conditions on the germination of seeds of Euphorbia heterophylla under controlled conditions.The experimental design was completely randomized design with four replications of 50 seeds, and the treatments were arranged in a 6 x 5 factorial, with six amount of sugarcane straw (0, 8, 10, 12, 14 and 16 t ha-1 and 5 types of light (constant light, constant darkness, alternating light and dark, short red and far red. The seeds were germinated in plastic type boxes covered byoverlapping layers of straw and kept in germination. Assessments of germination were daily computing the normal seedlings, when they presented protusion roots visible and calculated the germination speed index (IGS. It was observed that the increase of different densities of straw and different wave lengths provided germination ranged from 83 to 97% and IGS between 9.85 to 15.36. The different densities of straw and wavelength did not suppress the germination of E. heterophylla. Therefore, the species was insensitive to light, so the presence of raw sugarcane system can’t be considered a potential tool for controlling this species.Estudou-se a influência da densidade de palha de cana-de-açúcar e condições de luminosidade sobre a germinação de sementes de Euphorbia heterophylla em condições controladas. O delineamento experimental foi inteiramente casualizado, com quatro repetições de 50 sementes, e os tratamentos foram dispostos no esquema fatorial 6 x 5, sendo seis quantidades de palha de cana-de-açúcar (0, 8, 10, 12, 14 e 16 t ha-1 e cinco 5 tipos de luz (luz constante, escuro constante, alternância luz-escuro, vermelho curto e vermelho distante. As sementes foram colocadas para germinar em caixas plásticas do tipo gerbox e cobertas por camadas de palha sobrepostas e mantidas em câmaras de germinação. As avaliações de germinação foram diárias, computando-se as plântulas normais, quando

  11. In vivo imaging of germinal centres reveals a dynamic open structure.

    Science.gov (United States)

    Schwickert, Tanja A; Lindquist, Randall L; Shakhar, Guy; Livshits, Geulah; Skokos, Dimitris; Kosco-Vilbois, Marie H; Dustin, Michael L; Nussenzweig, Michel C

    2007-03-01

    Germinal centres are specialized structures wherein B lymphocytes undergo clonal expansion, class switch recombination, antibody gene diversification and affinity maturation. Three to four antigen-specific B cells colonize a follicle to establish a germinal centre and become rapidly dividing germinal-centre centroblasts that give rise to dark zones. Centroblasts produce non-proliferating centrocytes that are thought to migrate to the light zone of the germinal centre, which is rich in antigen-trapping follicular dendritic cells and CD4+ T cells. It has been proposed that centrocytes are selected in the light zone on the basis of their ability to bind cognate antigen. However, there have been no studies of germinal-centre dynamics or the migratory behaviour of germinal-centre cells in vivo. Here we report the direct visualization of B cells in lymph node germinal centres by two-photon laser-scanning microscopy in mice. Nearly all antigen-specific B cells participating in a germinal-centre reaction were motile and physically restricted to the germinal centre but migrated bi-directionally between dark and light zones. Notably, follicular B cells were frequent visitors to the germinal-centre compartment, suggesting that all B cells scan antigen trapped in germinal centres. Consistent with this observation, we found that high-affinity antigen-specific B cells can be recruited to an ongoing germinal-centre reaction. We conclude that the open structure of germinal centres enhances competition and ensures that rare high-affinity B cells can participate in antibody responses.

  12. Study of Seed Germination by Soaking Methode of Cacao (Theobroma cacao L.

    Directory of Open Access Journals (Sweden)

    Sulistyani Pancaningtyas

    2014-12-01

    Full Text Available Study of germination methods conduct to get information about seed viability based on germination rate, percentage of germination and vigority. Germination methods was studied to get the efficiency and effectivity of germination, easy to handle, low costs with high vigority. Sand and gunny sack methods  for germination, need extensive place  and 3-4 days germination period after planting. This research will study the alternative of germination method with soaking. This method can be accelerating  germination rate and effectively place usage without decreasing the quality of cacao seedling.The research was done at Kaliwining Experimental Station, Indonesian Coffee and Cocoa Research Institue. This research consist of two experiment was arranged based on factorial completely random design. First experiment will observed to compared germination rate and the second experiment will observed seedling quality between soaking and wet gunny sack germination method.The results showed that length of radicel on soaking method longer than wet gunny sack method. Growth of radicel started from 2 hours after soaking, moreover length of radicel at 4 hours after soaking have significant different value with gunny sack method. On 24 hours after soaking have 3,69 mm and 0,681 mm on wet gunny sack treatment. Except lengt of hipocotyl, there is not different condition between seedling that out came  from soaking and wet gunny sack method. Length of hipocotyl on 36 hours after soaking have 9,15 cm and significant different between wet gunny sack germination method that have 5,40 cm. Keywords : seed germination, soaking method, Theobroma cacao L., cocoa seedlings

  13. Nutritional assessment of barley, talbina and their germinated products

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    Mohamed kamal El-Sayed Youssef

    2013-02-01

    Full Text Available Talbina is a food product with high potential applications as a functional food. Talbina was prepared from two barley varieties namely: Giza126 and Giza130 by adding whole barley flour to water (1:10 w/v and (1:5 w/v for germinated barley then heating at  80° C for 5 minutes with continuous stirring until reaching a porridge like texture. The present investigation was carried out in an attempt to clearly the nutritional assessment of talbina as a functional food. The study included the determination of gross chemical composition, caloric value, mineral composition, vitamins composition and the amino acids composition. Meanwhile, computation of the chemical scores (CS and A/E ratios were carried out for raw, germinated barley, talbina, germinated talbina and commercial talbina. The data revealed that protein content of the all raw studied and processing treatments ranged from 8.75-18.34g/100g on dry weight basis. Besides, the all treatments recorded rather slight decrease in crude fat content. Likewise, ash and carbohydrates ranged between 2.29-2.86 and 73.40-82.66%, respectively. Whereas crude fiber had an increase after treatments and it ranged from 3.83-4.37%. On the other hand by making talbina iron, manganese, copper and zinc increased especially zinc, which recorded higher value than that recommended daily. Furthermore, germinated talbina130 recorded the highest amounts of vitamins B2, Nicotinic acid, B6 and folic acid. Moreover, the present study indicated that phenylalanine was the highest essential amino acid, followed by leucine.

  14. Fetal germinal matrix and intraventricular haemorrhage diagnosed by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Fukui, K.; Morioka, T.; Nishio, S.; Fukui, M. [Dept. of Neurosurgery, Kyushu Univ., Fukuoka (Japan); Mihara, F. [Dept. of Clinical Radiology, Kyushu Univ., Fukuoka (Japan); Nakayama, H. [Dept. of Paediatrics, Kyushu Univ., Fukuoka (Japan); Tsukimori, K. [Dept. of Obstetrics, Kyushu Univ., Fukuoka (Japan)

    2001-01-01

    Subependymal germinal matrix haemorrhage and intraventricular haemorrhage (GMIVH) is a common complication of delivery in preterm neonates but has rarely been observed in the fetus. We report two cases of GMIVH in fetuses of 36 weeks gestation, clearly demonstrated by antenatal MRI. In both cases progressive ventriculomegaly was observed, and ventriculoperitoneal shunts were placed at 19 and 6 months of age, respectively. Prenatal GMIVH may be a cause of congenital hydrocephalus, for which no aetiology has yet been found. (orig.)

  15. Desiccation effects on germination and vigor of King palm seeds

    OpenAIRE

    Martins Cibele C.; Bovi Marilene L. A.; Nakagawa João

    2003-01-01

    The desiccation tolerance of Archontophoenix alexandrae (Wendl. & Drude) seeds was determined and the most sensitive vigor test for assessing seed deterioration of this species was identified. Mature fruits were harvested in the palm collection of the Instituto Agronomico in Campinas, Brazil. Depulped fruits were transported in impermeable packages to the Faculdade de Agronomia in Botucatu, where the seeds were dried. As the seed moisture decreased, germination, seedling length, electrica...

  16. Fungal specificity bottlenecks during orchid germination and development.

    Science.gov (United States)

    Bidartondo, Martin I; Read, David J

    2008-08-01

    Fungus-subsidized growth through the seedling stage is the most critical feature of the life history for the thousands of mycorrhizal plant species that propagate by means of 'dust seeds.' We investigated the extent of specificity towards fungi shown by orchids in the genera Cephalanthera and Epipactis at three stages of their life cycle: (i) initiation of germination, (ii) during seedling development, and (iii) in the mature photosynthetic plant. It is known that in the mature phase, plants of these genera can be mycorrhizal with a number of fungi that are simultaneously ectomycorrhizal with the roots of neighbouring forest trees. The extent to which earlier developmental stages use the same or a distinctive suite of fungi was unclear. To address this question, a total of 1500 packets containing orchid seeds were buried for up to 3 years in diverse European forest sites which either supported or lacked populations of helleborine orchids. After harvest, the fungi associated with the three developmental stages, and with tree roots, were identified via cultivation-independent molecular methods. While our results show that most fungal symbionts are ectomycorrhizal, differences were observed between orchids in the representation of fungi at the three life stages. In Cephalanthera damasonium and C. longifolia, the fungi detected in seedlings were only a subset of the wider range seen in germinating seeds and mature plants. In Epipactis atrorubens, the fungi detected were similar at all three life stages, but different fungal lineages produced a difference in seedling germination performance. Our results demonstrate that there can be a narrow checkpoint for mycorrhizal range during seedling growth relative to the more promiscuous germination and mature stages of these plants' life cycle.

  17. [Grain filling dynamics and germination characteristics of Bupleurum chinense seeds].

    Science.gov (United States)

    Jin, Xin; Ren, Bing; Cao, Ai-Nong; Jin, Xiao-Jun

    2014-10-01

    Bupleurum chinense used in the study were cultivated in the experimental fields of Gansu agricultural University for three years. The seeds of B. chinense were collected every 3 days 10 d after the blossom. The result showed that the 1 000-grain fresh weight reached the maximum 43 d after the blossom and then decreased rapidly, at the mature period the fresh weight of seeds were falling to the same level of the dry weight. The dynamic change of the grain dry matter accumulation showed as an S-shape curve, the rapid increase stage was 25-34 d following the flower, and the grain filling was ended 46 d after blossom. Grain filling rate was under the law "fast-slow-fast-slow". And there were two peaks of grain filling rate appeared, after reached the second peak 28 d after the flower the filling rate decreased rapidly and stayed steadily 43 d after flowering. The dehydration rate was also measured at its maximum 43 d following flower. The indexes of seeds all reached the top 52 days following the blossom, when the germination rate reached the peak (34.33%) and water content of seeds was near 10%. The rate of germination and the 1 000-graid weight of seed showed significant positive correlation, while the water content of seeds was found significant negatively correlation with germination percentage. So the best time for harvest should be 52 d after flowering (9 month), the seeds collected at that time showed both high quality and germination rate.

  18. TLR7 influences germinal center selection in murine SLE.

    Science.gov (United States)

    Boneparth, Alexis; Huang, Weiqing; Bethunaickan, Ramalingam; Woods, Megan; Sahu, Ranjit; Arora, Shitij; Akerman, Meredith; Lesser, Martin; Davidson, Anne

    2015-01-01

    TLR7 enhances germinal center maturation and migration of B cells to the dark zone where proliferation and somatic hypermutation occur. Our goal was to determine how Tlr7 dose influences selection of the autoreactive B cell repertoire in NZW/BXSB. Yaa mice bearing the site-directed heavy chain transgene 3H9 that encodes for the TLR7 regulated anti-CL response. To create a physiologic setting in which autoreactive B cells compete for survival with non-autoreactive B cells, we generated bone marrow chimeras in which disease onset occurred with similar kinetics and the transferred 3H9+ female non-Yaa, male Yaa or male TLR7(-/Yaa) cells could be easily identified by positivity for GFP. Deletion of 3H9 B cells occurred in the bone marrow and the remaining 3H9 follicular B cells manifested a decrease in surface IgM. Although there were differences in the naïve repertoire between the chimeras it was not possible to distinguish a clear pattern of selection against lupus related autoreactivity in TLR7(-/Yaa) or female chimeras. By contrast, preferential expansion of 3H9+ B cells occurred in the germinal centers of male Yaa chimeras. In addition, although all chimeras preferentially selected 3H9/Vκ5 encoded B cells into the germinal center and plasma cell compartments, 3H9 male Yaa chimeras had a more diverse repertoire and positively selected the 3H9/Vκ5-48/Jκ4 pair that confers high affinity anti-cardiolipin activity. We were unable to demonstrate a consistent effect of Tlr7 dose or Yaa on somatic mutations. Our data show that TLR7 excess influences the selection, expansion and diversification of B cells in the germinal center, independent of other genes in the Yaa locus.

  19. Dynamics of phosphorus compounds in ripening and germinating cereal grains. Part II. Changes in phosphorus compounds content during germination of wheat, barley and rye grains

    Directory of Open Access Journals (Sweden)

    J. Tłuczkiewicz

    2015-01-01

    Full Text Available The dynamics of phosphorus compounds was investigated in the embryos and endosperm of wheat (Grana, barley (Kosmos and rye (Pancerne grain after 2, 4 and 6 days of germination. In germinating grain the phosphorus compounds transformations ran along the way of synthesis in the embryo and of breakdown in the endosperm. The level of phosphorus: inorganic, nucleotides, saccharides esters and their metabolites, lipid, RNA, DNA, phytin free and phytin bound with proteins and proteins rapidly increased in germinating seed embryos. The content of phosphorus free phytin and that bound with proteins, lipids, RNA and DNA in the endosperm rapidly decreased during germination. On the other hand, the saccharides phosphorus and that of their metabolites did not change, and inorganic, nuclotides and proteins-P slightly increased. Germinating rye grains showed a higher rate of synthesis in the embryos and of breakdown in the endosperm of the investigated phosphorus compounds than wheat and barley grains.

  20. Changes in germinal vesicle (GV) chromatin configurations during growth and maturation of porcine oocytes.

    Science.gov (United States)

    Sun, Xing-Shen; Liu, Yong; Yue, Kui-Zhong; Ma, Suo-Feng; Tan, Jing-He

    2004-10-01

    Changes in germinal vesicle (GV) chromatin configurations during growth and maturation of porcine oocytes were studied using a new method that allows a clearer visualization of both nucleolus and chromatin after Hoechst staining. The GV chromatin of porcine oocytes was classified into five configurations, based on the degree of chromatin condensation, and on nucleolus and nuclear membrane disappearance. While the GV1 to 4 configurations were similar to those reported by previous studies, the GV0 configuration was distinct by the diffuse, filamentous pattern of chromatin in the whole nuclear area. Most of the oocytes were at the GV0 stage in the layers of cumulus cells and those with less than one layer or no cumulus cells. Overall, our results suggested that (i) the GV0 configuration in porcine oocytes corresponded to the "nonsurrounded nucleolus" pattern in mice and other species; (ii) all the oocytes were synchronized at the GV1 stage before GVBD and this pattern might, therefore, represent a nonatretic state; (iii) the GV3 and GV4 configurations might represent stages toward atresia, or transient events prior to GVBD that could be switched toward either ovulation or atresia, depending upon circumstances; (iv) the in vitro systems currently used were not favorable for oocytes to switch toward ovulation (or final maturation); (v) the number of cumulus cells was not correlated with the chromatin configuration of oocytes, indicating that the beneficial effect of cumulus cells on oocyte maturation and development may simply be attributed to their presence during in vitro culture.