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Sample records for short-day induced dormancy

  1. Short day photoperiod protects against acetaminophen-induced ...

    African Journals Online (AJOL)

    Prof. Ogunji

    blood was collected by cardiac puncture for the estimation of liver enzymes activities. Liver ... revealed the protective effects of short photoperiod against acetaminophen-induced hepatotoxicity and lipid .... homogenized in ice cold KCl (100mM) containing. 0.003M ... This was followed by the addition of 1.0ml water and 5.0ml ...

  2. Gene expression changes during short day induced terminal bud formation in Norway spruce.

    Science.gov (United States)

    Asante, Daniel K A; Yakovlev, Igor A; Fossdal, Carl Gunnar; Holefors, Anna; Opseth, Lars; Olsen, Jorunn E; Junttila, Olavi; Johnsen, Øystein

    2011-02-01

    The molecular basis for terminal bud formation in autumn is not well understood in conifers. By combining suppression subtractive hybridization and monitoring of gene expression by qRT-PCR analysis, we aimed to identify genes involved in photoperiodic control of growth cessation and bud set in Norway spruce. Close to 1400 ESTs were generated and their functional distribution differed between short day (SD-12 h photoperiod) and long day (LD-24 h photoperiod) libraries. Many genes with putative roles in protection against stress appeared differentially regulated under SD and LD, and also differed in transcript levels between 6 and 20 SDs. Of these, PaTFL1(TERMINAL FLOWER LIKE 1) showed strongly increased transcript levels at 6 SDs. PaCCCH(CCCH-TYPE ZINC FINGER) and PaCBF2&3(C-REPEAT BINDING FACTOR 2&3) showed a later response at 20 SDs, with increased and decreased transcript levels, respectively. For rhythmically expressed genes such as CBFs, such differences might represent a phase shift in peak expression, but might also suggest a putative role in response to SD. Multivariate analyses revealed strong differences in gene expression between LD, 6 SD and 20 SD. The robustness of the gene expression patterns was verified in 6 families differing in bud-set timing under natural light with gradually decreasing photoperiod. © 2010 Blackwell Publishing Ltd.

  3. Treatment-Induced Autophagy Associated with Tumor Dormancy and Relapse

    Science.gov (United States)

    2017-07-01

    mechanisms make cellular transformation an inevitable event. Harmless somatic mutations have been reported in healthy hematopoietic stem cells of womenwith a...adult stem cells are also in a state of quiescent dormancy until they receive specific signals, such as tissue injury, to exit from dormancy and...lesions. RONS also induce DNA double- strand breaks, which can also be potently mutagenic if not accurately repaired. How- ever, detection of malignant

  4. NMDA receptor activation upstream of methyl farnesoate signaling for short day-induced male offspring production in the water flea, Daphnia pulex.

    Science.gov (United States)

    Toyota, Kenji; Miyakawa, Hitoshi; Yamaguchi, Katsushi; Shigenobu, Shuji; Ogino, Yukiko; Tatarazako, Norihisa; Miyagawa, Shinichi; Iguchi, Taisen

    2015-03-14

    The cladoceran crustacean Daphnia pulex produces female offspring by parthenogenesis under favorable conditions, but in response to various unfavorable external stimuli, it produces male offspring (environmental sex determination: ESD). We recently established an innovative system for ESD studies using D. pulex WTN6 strain, in which the sex of the offspring can be controlled simply by changes in the photoperiod: the long-day and short-day conditions can induce female and male offspring, respectively. Taking advantage of this system, we demonstrated that de novo methyl farnesoate (MF) synthesis is necessary for male offspring production. These results indicate the key role of innate MF signaling as a conductor between external environmental stimuli and the endogenous male developmental pathway. Despite these findings, the molecular mechanisms underlying up- and downstream signaling of MF have not yet been well elucidated in D. pulex. To elucidate up- and downstream events of MF signaling during sex determination processes, we compared the transcriptomes of daphnids reared under the long-day (female) condition with short-day (male) and MF-treated (male) conditions. We found that genes involved in ionotropic glutamate receptors, known to mediate the vast majority of excitatory neurotransmitting processes in various organisms, were significantly activated in daphnids by the short-day condition but not by MF treatment. Administration of specific agonists and antagonists, especially for the N-methyl-D-aspartic acid (NMDA) receptor, strongly increased or decreased, respectively, the proportion of male-producing mothers. Moreover, we also identified genes responsible for male production (e.g., protein kinase C pathway-related genes). Such genes were generally shared between the short-day reared and MF-treated daphnids. We identified several candidate genes regulating ESD which strongly suggests that these genes may be essential factors for male offspring production as an

  5. Targeting Neutrophil Protease-Mediated Degradation of Tsp-1 to Induce Metastatic Dormancy

    Science.gov (United States)

    2017-10-01

    AWARD NUMBER: W81XWH-16-1-0615 TITLE: Targeting Neutrophil Protease-Mediated Degradation of Tsp-1 to Induce Metastatic Dormancy PRINCIPAL...29 Sep 2017 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Targeting Neutrophil Protease-Mediated Degradation of Tsp-1 to Induce Metastatic Dormancy...infection or cigarette smoke enhanced pulmonary metastasis from breast cancer in humans and mice. Similarly, autoimmune arthritis, characterized by

  6. BMP7 Induces Dormancy of Prostatic Tumor Stem Cell in Bone

    Science.gov (United States)

    2013-07-01

    of NDRG1 is correlated with tumor progression and poor prog- nosis in patients with esophageal squamous cell carcinoma. Dis. Esophagus . 19:454–458...Dormancy of Prostatic Tumor Stem Cell in Bone PRINCIPAL INVESTIGATOR: Fei Xing, Ph.D...BMP7 Induces Dormancy of Prostatic Tumor Stem Cell in Bone 5b. GRANT NUMBER W81XWH-10-1-0666 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Fei

  7. Seed dormancy and germination.

    Science.gov (United States)

    Penfield, Steven

    2017-09-11

    Reproduction is a critical time in plant life history. Therefore, genes affecting seed dormancy and germination are among those under strongest selection in natural plant populations. Germination terminates seed dispersal and thus influences the location and timing of plant growth. After seed shedding, germination can be prevented by a property known as seed dormancy. In practise, seeds are rarely either dormant or non-dormant, but seeds whose dormancy-inducing pathways are activated to higher levels will germinate in an ever-narrower range of environments. Thus, measurements of dormancy must always be accompanied by analysis of environmental contexts in which phenotypes or behaviours are described. At its simplest, dormancy can be imposed by the formation of a simple physical barrier around the seed through which gas exchange and the passage of water are prevented. Seeds featuring this so-called 'physical dormancy' often require either scarification or passage through an animal gut (replete with its associated digestive enzymes) to disrupt the barrier and permit germination. In other types of seeds with 'morphological dormancy' the embryo remains under-developed at maturity and a dormant phase exists as the embryo continues its growth post-shedding, eventually breaking through the surrounding tissues. By far, the majority of seeds exhibit 'physiological dormancy' - a quiescence program initiated by either the embryo or the surrounding endosperm tissues. Physiological dormancy uses germination-inhibiting hormones to prevent germination in the absence of the specific environmental triggers that promote germination. During and after germination, early seedling growth is supported by catabolism of stored reserves of protein, oil or starch accumulated during seed maturation. These reserves support cell expansion, chloroplast development and root growth until photoauxotrophic growth can be resumed. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  8. Nutrient enrichment induces dormancy and decreases diversity of active bacteria in salt marsh sediments

    Science.gov (United States)

    Kearns, Patrick J.; Angell, John H.; Howard, Evan M.; Deegan, Linda A.; Stanley, Rachel H. R.; Bowen, Jennifer L.

    2016-09-01

    Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that control the proportion of active microbes in the environment and how they vary when perturbed is critical to anticipating ecosystem response to global change. Increasing supplies of anthropogenic nitrogen to ecosystems globally makes it imperative that we understand how nutrient supply alters active microbial communities. Here we show that nitrogen additions to salt marshes cause a shift in the active microbial community despite no change in the total community. The active community shift causes the proportion of dormant microbial taxa to double, from 45 to 90%, and induces diversity loss in the active portion of the community. Our results suggest that perturbations to salt marshes can drastically alter active microbial communities, however these communities may remain resilient by protecting total diversity through increased dormancy.

  9. Characterization of a Mycobacterium smegmatis uvrA mutant impaired in dormancy induced by hypoxia and low carbon concentration

    Directory of Open Access Journals (Sweden)

    Calabrese Immacolata

    2011-10-01

    Full Text Available Abstract Background The aerobic fast-growing Mycobacterium smegmatis, like its slow-growing pathogenic counterpart Mycobacterium tuberculosis, has the ability to adapt to microaerobiosis by shifting from growth to a non-proliferating or dormant state. The molecular mechanism of dormancy is not fully understood and various hypotheses have been formulated to explain it. In this work, we open new insight in the knowledge of M. smegmatis dormancy, by identifying and characterizing genes involved in this behavior. Results In a library generated by transposon mutagenesis, we searched for M. smegmatis mutants unable to survive a coincident condition of hypoxia and low carbon content, two stress factors supposedly encountered in the host and inducing dormancy in tubercle bacilli. Two mutants were identified that mapped in the uvrA gene, coding for an essential component of the Nucleotide Excision Repair system (NER. The two mutants showed identical phenotypes, although the respective transposon insertions hit different regions of the uvrA gene. The restoration of the uvrA activity in M. smegmatis by complementation with the uvrA gene of M. tuberculosis, confirmed that i uvrA inactivation was indeed responsible for the inability of M. smegmatis cells to enter or exit dormancy and, therefore, survive hypoxia and presence of low carbon and ii showed that the respective uvrA genes of M. tuberculosis and M. smegmatis are true orthologs. The rate of survival of wild type, uvrA mutant and complemented strains under conditions of oxidative stress and UV irradiation was determined qualitatively and quantitatively. Conclusions Taken together our results confirm that the mycobacterial NER system is involved in adaptation to various stress conditions and suggest that cells with a compromised DNA repair system have an impaired dormancy behavior.

  10. Roles of gibberellin catabolism and signaling in growth and physiological response to drought and short-day photoperiods in Populus trees.

    Directory of Open Access Journals (Sweden)

    Christine Zawaski

    Full Text Available Survival and productivity of perennial plants in temperate zones are dependent on robust responses to prolonged and seasonal cycles of unfavorable conditions. Here we report whole-genome microarray, expression, physiological, and transgenic evidence in hybrid poplar (Populus tremula × Populus alba showing that gibberellin (GA catabolism and repressive signaling mediates shoot growth inhibition and physiological adaptation in response to drought and short-day (SD induced bud dormancy. Both water deprivation and SDs elicited activation of a suite of poplar GA2ox and DELLA encoding genes. Poplar transgenics with up-regulated GA 2-oxidase (GA2ox and DELLA domain proteins showed hypersensitive growth inhibition in response to both drought and SDs. In addition, the transgenic plants displayed greater drought resistance as evidenced by increased pigment concentrations (chlorophyll and carotenoid and reductions in electrolyte leakage (EL. Comparative transcriptome analysis using whole-genome microarray showed that the GA-deficiency and GA-insensitivity, SD-induced dormancy, and drought response in poplar share a common regulon of 684 differentially-expressed genes, which suggest GA metabolism and signaling plays a role in plant physiological adaptations in response to alterations in environmental factors. Our results demonstrate that GA catabolism and repressive signaling represents a major route for control of growth and physiological adaptation in response to immediate or imminent adverse conditions.

  11. Regulation of wheat seed dormancy by after-ripening is mediated by specific transcriptional switches that induce changes in seed hormone metabolism and signaling.

    Directory of Open Access Journals (Sweden)

    Aihua Liu

    Full Text Available Treatments that promote dormancy release are often correlated with changes in seed hormone content and/or sensitivity. To understand the molecular mechanisms underlying the role of after-ripening (seed dry storage in triggering hormone related changes and dormancy decay in wheat (Triticum aestivum, temporal expression patterns of genes related to abscisic acid (ABA, gibberellin (GA, jasmonate and indole acetic acid (IAA metabolism and signaling, and levels of the respective hormones were examined in dormant and after-ripened seeds in both dry and imbibed states. After-ripening mediated developmental switch from dormancy to germination appears to be associated with declines in seed sensitivity to ABA and IAA, which are mediated by transcriptional repressions of PROTEIN PHOSPHATASE 2C, SNF1-RELATED PROTEIN KINASE2, ABA INSENSITIVE5 and LIPID PHOSPHATE PHOSPHTASE2, and AUXIN RESPONSE FACTOR and RELATED TO UBIQUITIN1 genes. Transcriptomic analysis of wheat seed responsiveness to ABA suggests that ABA inhibits the germination of wheat seeds partly by repressing the transcription of genes related to chromatin assembly and cell wall modification, and activating that of GA catabolic genes. After-ripening induced seed dormancy decay in wheat is also associated with the modulation of seed IAA and jasmonate contents. Transcriptional control of members of the ALLENE OXIDE SYNTHASE, 3-KETOACYL COENZYME A THIOLASE, LIPOXYGENASE and 12-OXOPHYTODIENOATE REDUCTASE gene families appears to regulate seed jasmonate levels. Changes in the expression of GA biosynthesis genes, GA 20-OXIDASE and GA 3-OXIDASE, in response to after-ripening implicate this hormone in enhancing dormancy release and germination. These findings have important implications in the dissection of molecular mechanisms underlying regulation of seed dormancy in cereals.

  12. Financial results achieved in short-day strawberry production

    Directory of Open Access Journals (Sweden)

    Galić Dragan

    2014-01-01

    Full Text Available In South-western Ontario's continental climate (short days, hot summers and very cold winters the matted-row system was the dominant production system to grow short-day strawberries. Varieties-staggered production (planting a combination of early, mid and late-season varieties provides strawberry harvest from five to seven weeks. Short-day strawberries are vegetative grown in the first year, and harvested for two consecutive years. The total cost of short-day strawberry production was 54,370 $CAD/ha. The production and harvest costs in the first and second years were 20,812 $CAD/ha and 16,930 $CAD/ ha, respectively, and accounted for 69.42% of the total. Pre-plans operations were the least expensive procedures costing 8.13%, while planting and care of young plants made up 22.45% of the total costs. The total income of growing short-day strawberries under a matted-row system was 76,671 $CAD/ha (the first and second production years 41,330 $CAD/ha and 35,341 $CAD/ha, respectively. The short-day strawberries in matted-row system, with average yield of 15,722 kg/ha, generated a net revenue of 22,300 $CAD/ha.

  13. The role of zeatin and gibberellic acid in breaking of the abscisic acid-induced dormancy in Triticale caryopses

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    Stanisław Weidner

    2014-01-01

    Full Text Available The investigations were conducted on the germinating embryos and the whole caryopses of Triticale. During preimbibition and 24 hours germination caryopses were treated with abscisic acid (ABA, which produced 63% inhibition of embryo growth. Gibberellin-A3 (GA3 reversed the ABA effect in 18%, while zeatin in 22%. The clear synergic reaction was observed (36% when both stimulators acted together. There was no significant effect of ABA, ABA and GA3, as well as ABA and zeatin on the synthesis of polyribosomal RNA in the initial period of germination of excised embryos. However, during 24 hours germination of whole caryopses ABA caused a twofold decrease in 3H-uridine incorporation into the total fraction of embryonic ribosomes. While the incorporation of 14C-aminoacid mixture into ribosomal proteins was even three-fold lower. Effect of GA3 and zeatin on breaking of the ABA-induced "dormancy" was studied. It was confirmed that the higher polyribosome contribution to the sum total of ribosomes the more intensive synthesis of ribosomal proteins. No higher 3H-uridine incorporation into polyribosomal fraction was observed. From the results it may be inferred that in the initial period of germination of Triticale caryopses regulation of protein biosynthesis occurs rather at the translation than transcription level.

  14. Growth of short-day treated spruce seedlings planted throughout British Columbia. FRDA report No. 209

    Energy Technology Data Exchange (ETDEWEB)

    Krasowski, M.J.; Letchford, T.; Eastham, A.M.

    1993-01-01

    Short photoperiod (SD) treatments of conifer seedlings induce bud dormancy and enhance cold acclimation. Such treatments are also useful in regulating seedling height to meet a specific target and in preparing seedlings for lifting at a desirable time. These trials were designed to compare different SD-treated and untreated stock in terms of their annual height and ground-line stem diameter increments, 1st year post-planting terminal bud phenology, and seedling survival and condition.

  15. Is Impatiens balsamina a qualitative short-day plant?

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    Elżbieta Teske

    2014-01-01

    Full Text Available Impatiens balsamina which, in literature on the physiology of flowering, is assigned to qualitative short-day plants, flowers under Polish climatic conditions from June until September. It flowers, therefore. during the period of the longest day. The photoperiodic responses of I. balsamina plants raised from seeds obtained from botanical gardens located within the range of 23 -65° N. lat. were studied. The experiment revealed marked differences in the photoperiodic responses within the species. Qualitative short-day plants, quantitative short-day plants and day-neutral plants were found in the studied material. An evident correlation was found between the place of origin of the studied seeds and the photoperiodic sensitivity of the plants raised from them.

  16. Toxin ζ Reversible Induces Dormancy and Reduces the UDP-N-Acetylglucosamine Pool as One of the Protective Responses to Cope with Stress

    Directory of Open Access Journals (Sweden)

    Mariangela Tabone

    2014-09-01

    Full Text Available Toxins of the ζ/PezT family, found in the genome of major human pathogens, phosphorylate the peptidoglycan precursor uridine diphosphate-N-acetylglucosamine (UNAG leading to unreactive UNAG-3P. Transient over-expression of a PezT variant impairs cell wall biosynthesis and triggers autolysis in Escherichia coli. Conversely, physiological levels of ζ reversibly induce dormancy produce a sub-fraction of membrane-compromised cells, and a minor subpopulation of Bacillus subtilis cells become tolerant of toxin action. We report here that purified ζ is a strong UNAG-dependent ATPase, being GTP a lower competitor. In vitro, ζ toxin phosphorylates a fraction of UNAG. In vivo, ζ-mediated inactivation of UNAG by phosphorylation does not deplete the active UNAG pool, because expression of the toxin enhances the efficacy of genuine cell wall inhibitors (fosfomycin, vancomycin or ampicillin. Transient ζ expression together with fosfomycin treatment halt cell proliferation, but ε2 antitoxin expression facilitates the exit of ζ-induced dormancy, suggesting that there is sufficient UNAG for growth. We propose that ζ induces diverse cellular responses to cope with stress, being the reduction of the UNAG pool one among them. If the action of ζ is not inhibited, e.g., by de novo ε2 antitoxin synthesis, the toxin markedly enhances the efficacy of antimicrobial treatment without massive autolysis in Firmicutes.

  17. Dormancy in Plant Seeds

    NARCIS (Netherlands)

    Hilhorst, H.W.M.; Finch-Savage, W.E.; Buitink, J.; Bolingue, W.; Leubner-Metzger, G.

    2010-01-01

    Seed dormancy has been studied intensely over the past decades and, at present, knowledge of this plant trait is at the forefront of plant biology. The main model species is Arabidopsis thaliana, an annual weed, possessing nondeep physiological dormancy. This overview presents the state-of-the-art

  18. [Factors inducing transition from growth to dormancy in rhizobacteria Azospirillum brasilense].

    Science.gov (United States)

    Kushneruk, M A; Tugarova, A V; Il'chukova, A V; Slavkina, E A; Starichkova, N I; Bogatyrev, V A; Antoniuk, L P

    2013-01-01

    The factors suppressing division of the cells of the rhizobacterium Azospirillum brasilense and inducing their transition to a dormant state were analyzed. These included the presence of hexylresorcinol or heavy metals (Cu and Co) in the medium, oxygen stress, and transfer of the cells into the physiological saline or phosphate buffer solution. The results were used to develop a protocol for obtaining of uncultured cells of A. brasilense Sp245, a natural symbiont of wheat. The cells lost their ability to grow on synthetic agar medium, but could revert to growth when incubated in freshly prepared liquid medium. Needle-shaped crystals differing from struvite, which has been previously reported for this strain, were found in the dormant culture of A. brasilense Sp245.

  19. Salt Induces Features of a Dormancy-Like State in Seeds of Eutrema (Thellungiella salsugineum, a Halophytic Relative of Arabidopsis

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    Yana Kazachkova

    2016-08-01

    Full Text Available The salinization of land is a major factor limiting crop production worldwide. Halophytes adapted to high levels of salinity are likely to possess useful genes for improving crop tolerance to salt stress, as well as providing a food source on marginal lands. However, despite being salt-tolerant plants, the seeds of many halophytes will not germinate on saline soils, yet little is understood regarding biochemical and gene expression changes underlying salt-mediated inhibition of halophyte seed germination. We have used the halophytic Arabidopsis relative model system, Eutrema (Thellungiella salsugineum to explore salt-mediated inhibition of germination. We show that E. salsugineum seed germination is inhibited by salt to a far greater extent than in Arabidopsis, and that this inhibition is in response to the osmotic component of salt exposure. E. salsugineum seeds remain viable even when germination is completely inhibited, and germination resumes once seeds are transferred to non-saline conditions. Moreover, removal of the seed coat from salt-treated seeds allows embryos to germinate on salt-containing medium. Mobilization of seed storage reserves is restricted in salt-treated seeds, while many germination-associated metabolic changes are arrested or progress to a lower extent. Salt-exposed seeds are further characterized by a reduced GA/ABA ratio and increased expression of the germination repressor genes, RGL2, ABI5 and DOG1. Furthermore, a salt-mediated increase in expression of a LATE EMBRYOGENESIS ABUNDANT gene and accretion of metabolites involved in osmoprotection indicates induction of processes associated with stress tolerance, and accumulation of easily mobilized carbon reserves. Overall, our results suggest that salt inhibits E. salsugineum seed germination by inducing a seed state with molecular features of dormancy while a physical constraint to radicle emergence is provided by the seed coat layers. This seed state could facilitate

  20. Chilling of dormant buds hyperinduces FLOWERING LOCUS T and recruits GA-inducible 1,3-beta-glucanases to reopen signal conduits and release dormancy in Populus.

    Science.gov (United States)

    Rinne, Päivi L H; Welling, Annikki; Vahala, Jorma; Ripel, Linda; Ruonala, Raili; Kangasjärvi, Jaakko; van der Schoot, Christiaan

    2011-01-01

    In trees, production of intercellular signals and accessibility of signal conduits jointly govern dormancy cycling at the shoot apex. We identified 10 putative cell wall 1,3-β-glucanase genes (glucan hydrolase family 17 [GH17]) in Populus that could turn over 1,3-β-glucan (callose) at pores and plasmodesmata (PD) and investigated their regulation in relation to FT and CENL1 expression. The 10 genes encode orthologs of Arabidopsis thaliana BG_ppap, a PD-associated glycosylphosphatidylinositol (GPI) lipid-anchored protein, the Arabidopsis PD callose binding protein PDCB, and a birch (Betula pendula) putative lipid body (LB) protein. We found that these genes were differentially regulated by photoperiod, by chilling (5°C), and by feeding of gibberellins GA(3) and GA(4). GA(3) feeding upregulated all LB-associated GH17s, whereas GA(4) upregulated most GH17s with a GPI anchor and/or callose binding motif, but only GA(4) induced true bud burst. Chilling upregulated a number of GA biosynthesis and signaling genes as well as FT, but not CENL1, while the reverse was true for both GA(3) and GA(4). Collectively, the results suggest a model for dormancy release in which chilling induces FT and both GPI lipid-anchored and GA(3)-inducible GH17s to reopen signaling conduits in the embryonic shoot. When temperatures rise, the reopened conduits enable movement of FT and CENL1 to their targets, where they drive bud burst, shoot elongation, and morphogenesis.

  1. Redefining reproductive dormancy in Drosophila as a general stress response to cold temperatures.

    Science.gov (United States)

    Lirakis, Manolis; Dolezal, Marlies; Schlötterer, Christian

    2018-04-09

    Organisms regularly encounter unfavorable conditions and the genetic adaptations facilitating survival have been of long-standing interest to evolutionary biologists. Winter is one particularly stressful condition for insects, during which they encounter low temperatures and scarcity of food. Despite dormancy being a well-studied adaptation to facilitate overwintering, there is still considerable controversy about the distribution of dormancy among natural populations and between species in Drosophila. The current definition of dormancy as developmental arrest of oogenesis at the previtellogenic stage (stage 7) distinguishes dormancy from general stress related block of oogenesis at early vitellogenic stages (stages 8 - 9). In an attempt to resolve this, we scrutinized reproductive dormancy in D. melanogaster and D. simulans. We show that dormancy shows the same hallmarks of arrest of oogenesis at stage 9, as described for other stressors and propose a new classification for dormancy. Applying this modified classification, we show that both species express dormancy in cosmopolitan and African populations, further supporting that dormancy uses an ancestral pathway induced by environmental stress. While we found significant differences between individuals and the two Drosophila species in their sensitivity to cold temperature stress, we also noted that extreme temperature stress (8 °C) resulted in very strong dormancy incidence, which strongly reduced the differences seen at less extreme temperatures. We conclude that dormancy in Drosophila should not be considered a special trait, but is better understood as a generic stress response occurring at low temperatures. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Seed dormancy and germination

    NARCIS (Netherlands)

    Bentsink, L.; Koornneef, M.

    2002-01-01

    Arabidopsis possesses dormancy, as is the case for many other plant species, which is controlled by environmental factors such as light, temperature and time of dry storage as well as by genetic factors. The use of genetics and molecular genetics in Arabidopsis is starting to shed light on some

  3. Dormancy in breast cancer

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    Banys M

    2012-12-01

    Full Text Available Malgorzata Banys,1,2 Andreas D Hartkopf,1 Natalia Krawczyk,1 Tatjana Kaiser,1 Franziska Meier-Stiegen,1 Tanja Fehm,1 Hans Neubauer11Department of Obstetrics and Gynecology, University of Tuebingen, Tuebingen, Germany; 2Department of Obstetrics and Gynecology, Marienkrankenhaus Hamburg, Hamburg, GermanyAbstract: Tumor dormancy describes a prolonged quiescent state in which tumor cells are present, but disease progression is not yet clinically apparent. Breast cancer is especially known for long asymptomatic periods, up to 25 years, with no evidence of the disease, followed by a relapse. Factors that determine the cell's decision to enter a dormant state and that control its duration remain unclear. In recent years, considerable progress has been made in understanding how tumor cells circulating in the blood interact and extravasate into secondary sites and which factors might determine whether these cells survive, remain dormant, or become macrometastases. The mechanisms of tumor cell dormancy are still not clear. Two different hypotheses are currently discussed: tumor cells persist either by completely withdrawing from the cell cycle or by continuing to proliferate at a slow rate that is counterbalanced by cell death. Because dormant disseminated tumor cells may be the founders of metastasis, one hypothesis is that dormant tumor cells, or at least a fraction of them, share stem cell-like characteristics that may be responsible for their long half-lives and their suggested resistance to standard chemotherapy. Therefore, knowledge of the biology of tumor cell dormancy may be the basis from which to develop innovative targeted therapies to control or eliminate this tumor cell fraction. In this review, we discuss biological mechanisms and clinical implications of tumor dormancy in breast cancer patients.Keywords: tumor dormancy, disseminated tumor cell, circulating tumor cell, targeted therapy

  4. Behavioral Senescence and Aging-Related Changes in Motor Neurons and Brain Neuromodulator Levels Are Ameliorated by Lifespan-Extending Reproductive Dormancy in Drosophila

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    Dick R. Nässel

    2017-04-01

    Full Text Available The lifespan of Drosophilamelanogaster can be extended substantially by inducing reproductive dormancy (also known as diapause by lowered temperature and short days. This increase of longevity is accompanied by lowered metabolism and increased stress tolerance. We ask here whether behavioral senescence is ameliorated during adult dormancy. To study this we kept flies for seven or more weeks in normal rearing conditions or in diapause conditions and compared to 1-week-old flies in different behavioral assays of sleep, negative geotaxis and exploratory walking. We found that the senescence of geotaxis and locomotor behavior seen under normal rearing conditions was negligible in flies kept in dormancy. The normal senescence of rhythmic activity and sleep patterns during the daytime was also reduced by adult dormancy. Investigating the morphology of specific neuromuscular junctions (NMJs, we found that changes normally seen with aging do not take place in dormant flies. To monitor age-associated changes in neuronal circuits regulating activity rhythms, sleep and walking behavior we applied antisera to tyrosine hydroxylase (TH, serotonin and several neuropeptides to examine changes in expression levels and neuron morphology. In most neuron types the levels of stored neuromodulators decreased during normal aging, but not in diapause treated flies. No signs of neurodegeneration were seen in either condition. Our data suggest that age-related changes in motor neurons could be the cause of part of the behavioral senescence and that this is ameliorated by reproductive diapause. Earlier studies established a link between age-associated decreases in neuromodulator levels and behavioral decline that could be rescued by overexpression of neuromodulator. Thus, it is likely that the retained levels of neuromodulators in dormant flies alleviate behavioral senescence.

  5. Experiences with dormancy in tardigrades

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    Deborah BOSCHINI

    2004-09-01

    Full Text Available Tardigrades often colonise extreme habitats, in which they survive using both types of dormancy: quiescence and diapause. Together with nematodes and bdelloid rotifers, tardigrades are known to enter quiescence (with several forms of cryptobiosis: anhydrobiosis, cryobiosis, anoxybiosis, osmobiosis at any stage of their life cycle, from egg to adult. Entering anhydrobiosis, tardigrades contract their body into a so-called tun, loosing most of their free and bound water (>95%, synthesizing cell protectants (e.g., trehalose, glycerol, heat shock proteins and strongly reducing or suspending their metabolism. Our research on cryptobiosis focused on some ecological and evolutionary aspects. We evaluated: i the long-term anhydrobiotic survival by comparing quantitative data on recovery from naturally induced desiccation in several species of tardigrades; ii differences in survival patterns between species and populations by experimentally inducing anhydrobiosis and cryobiosis; iii phenotypic factors affecting anhydrobiotic survival. As regards diapause, we considered encystment and eggs. Encystment involves at least the synthesis of new cuticular structures. Morphological changes during cyst formation are more complex than those involved in tun formation. We analyzed more in detail encystment processes, comparing a semiterrestrial with a limnic species. Several inter-specific differences have been identified, other than the production of two types of cysts in the semiterrestrial species. Our analysis of life history traits of a laboratory reared strain of a soil tardigrade revealed a particular hatching phenology that involved the production of both subitaneous and resting eggs. The latter need a cue to hatch (dehydration followed by re-hydration. In addition, the evolutionary meaning of dormancy in tardigrades is discussed.

  6. Seed after-ripening and dormancy determine adult life history independently of germination timing.

    Science.gov (United States)

    de Casas, Rafael Rubio; Kovach, Katherine; Dittmar, Emily; Barua, Deepak; Barco, Brenden; Donohue, Kathleen

    2012-05-01

    • Seed dormancy can affect life history through its effects on germination time. Here, we investigate its influence on life history beyond the timing of germination. • We used the response of Arabidopsis thaliana to chilling at the germination and flowering stages to test the following: how seed dormancy affects germination responses to the environment; whether variation in dormancy affects adult phenology independently of germination time; and whether environmental cues experienced by dormant seeds have an effect on adult life history. • Dormancy conditioned the germination response to low temperatures, such that prolonged periods of chilling induced dormancy in nondormant seeds, but stimulated germination in dormant seeds. The alleviation of dormancy through after-ripening was associated with earlier flowering, independent of germination date. Experimental dormancy manipulations showed that prolonged chilling at the seed stage always induced earlier flowering, regardless of seed dormancy. Surprisingly, this effect of seed chilling on flowering time was observed even when low temperatures did not induce germination. • In summary, seed dormancy influences flowering time and hence life history independent of its effects on germination timing. We conclude that the seed stage has a pronounced effect on life history, the influence of which goes well beyond the timing of germination. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  7. Identification of genes associated with growth cessation and bud dormancy entrance using a dormancy-incapable tree mutant.

    Science.gov (United States)

    Jiménez, Sergio; Li, Zhigang; Reighard, Gregory L; Bielenberg, Douglas G

    2010-02-09

    In many tree species the perception of short days (SD) can trigger growth cessation, dormancy entrance, and the establishment of a chilling requirement for bud break. The molecular mechanisms connecting photoperiod perception, growth cessation and dormancy entrance in perennials are not clearly understood. The peach [Prunus persica (L.) Batsch] evergrowing (evg) mutant fails to cease growth and therefore cannot enter dormancy under SD. We used the evg mutant to filter gene expression associated with growth cessation after exposure to SD. Wild-type and evg plants were grown under controlled conditions of long days (16 h/8 h) followed by transfer to SD (8 h/16 h) for eight weeks. Apical tissues were sampled at zero, one, two, four, and eight weeks of SD and suppression subtractive hybridization was performed between genotypes at the same time points. We identified 23 up-regulated genes in the wild-type with respect to the mutant during SD exposure. We used quantitative real-time PCR to verify the expression of the differentially expressed genes in wild-type tissues following the transition to SD treatment. Three general expression patterns were evident: one group of genes decreased at the time of growth cessation (after 2 weeks in SD), another that increased immediately after the SD exposure and then remained steady, and another that increased throughout SD exposure. The use of the dormancy-incapable mutant evg has allowed us to reduce the number of genes typically detected by differential display techniques for SD experiments. These genes are candidates for involvement in the signalling pathway leading from photoperiod perception to growth cessation and dormancy entrance and will be the target of future investigations.

  8. Seed dormancy and seed longevity: from genetic variation to gene identification

    NARCIS (Netherlands)

    Nguyen, T.P.

    2014-01-01

    Seed dormancy and seed longevity are the most important survival traits in the soil seed bank. Both traits are induced during seed maturation and evolved to assure seed survival during environmental conditions that cannot support the regular course of life. Seed dormancy is related to the timing of

  9. Water deficit severity during berry development alters timing of dormancy transitions in wine grape cultivar Malbec

    Science.gov (United States)

    The objective of this study was to test the hypothesis that vine water stress during the growing season can lengthen the dormancy cycle by inducing earlier transition into endodormancy. A bud forcing assay was used to compare the dormancy transitions of field-grown ‘Malbec’ grapevines that had been ...

  10. Maternal environment affects the genetic basis of seed dormancy in Arabidopsis thaliana.

    Science.gov (United States)

    Postma, Froukje M; Ågren, Jon

    2015-02-01

    The genetic basis of seed dormancy, a key life history trait important for adaptive evolution in plant populations, has yet been studied only using seeds produced under controlled conditions in greenhouse environments. However, dormancy is strongly affected by maternal environmental conditions, and interactions between seed genotype and maternal environment have been reported. Consequently, the genetic basis of dormancy of seeds produced under natural field conditions remains unclear. We examined the effect of maternal environment on the genetic architecture of seed dormancy using a recombinant inbred line (RIL) population derived from a cross between two locally adapted populations of Arabidopsis thaliana from Italy and Sweden. We mapped quantitative trait loci (QTL) for dormancy of seeds produced in the greenhouse and at the native field sites of the parental genotypes. The Italian genotype produced seeds with stronger dormancy at fruit maturation than did the Swedish genotype in all three environments, and the maternal field environments induced higher dormancy levels compared to the greenhouse environment in both genotypes. Across the three maternal environments, a total of nine dormancy QTL were detected, three of which were only detected among seeds matured in the field, and six of which showed significant QTL × maternal environment interactions. One QTL had a large effect on dormancy across all three environments and colocalized with the candidate gene DOG1. Our results demonstrate the importance of studying the genetic basis of putatively adaptive traits under relevant conditions. © 2015 John Wiley & Sons Ltd.

  11. Comprehensive Cloning of Prunus mume Dormancy Associated MADS-Box Genes and Their Response in Flower Bud Development and Dormancy

    Directory of Open Access Journals (Sweden)

    Kai Zhao

    2018-02-01

    Full Text Available Dormancy Associated MADS-box genes are SVP/MADs-box members and supposed to play crucial roles in plant dormancy of perennial species. In Prunus mume, PmDAM6 has been previously identified to induce plant dormancy. In the current study, six PmDAMs were cloned in P. mume and functionally analyzed in yeast and tobacco to detect the roles of the genes paralogous to PmDAM6. The expression patterns together with sequence similarities indicate that PmDAMs are divided into two sub-clades within SVP group. Moreover, PmDAMs are verified to take part in the development of different plant organs, specifically the flower buds, in some intricate patterns. Furthermore, the PmDAM proteins are found to have special functions by forming corresponding protein complex during the development of flower bud and induction of dormancy. In particular, when PmDAM1 dominating in flower bud in the warm months, the protein complexes are consisted of PmDAM1 itself or with PmDAM2. With the decrease temperatures in the following months, PmDAM6 was found to be highly expressed and gradually changed the complex structure to PmDAM6-protein complex due to strong binding tendencies with PmDAM1 and PmDAM3. Finally, the homodimers of PmDAM6 prevailed to induce the dormancy. The results obtained in the current study highlight the functions of PmDAMs in the tissue development and dormancy, which provide available suggestions for further explorations of protein-complex functions in association with bud growth and dormancy.

  12. Adrenal, thyroid, and testicular hormone rhythms in male golden hamsters on long and short days

    International Nuclear Information System (INIS)

    Ottenweller, J.E.; Tapp, W.N.; Pitman, D.L.; Natelson, B.H.

    1987-01-01

    Plasma concentrations of adrenal, thyroid, and testicular hormones were measured at 4-h intervals around the clock in male hamsters on long (14:10-h light-dark cycle) and short (10:14-h light-dark cycle) days. Plasma corticosterone, cortisol, thyroxine (T 4 ), triiodothyronine (T 3 ), and testosterone rhythms were present on long days. The only one of these hormones to have a significant rhythm on short days was cortisol, but even its amplitude was suppressed compared with the cortisol rhythm on long days. Short days also lowered mean plasma levels of cortisol, T 4 , T 3 , and testosterone. Finally, short days raised the ratio of corticosterone to cortisol and lowered the ratio of T 4 to T 3 . Both ratios had significant rhythms on long days but not on short days. Because of the many interactions among adrenal, thyroid, and testicular hormone axes, it is unclear whether the primary effect of short days is on one of these endocrine systems or on another factor that has separate effects on each of the hormone rhythms that was measured. Nonetheless, it is clear that a major effect of short day lengths in hamsters is to suppress hormone rhythms. Explanations of photoperiodic effects that depend on endocrine mediation should take this into account

  13. Effect of different treatments on breaking dormancy of Teucrium polium

    Directory of Open Access Journals (Sweden)

    alireza koochaki

    2009-06-01

    Full Text Available In order to evaluate effects of different treatments on breaking dormancy of Teucrium polium, an experiment was conducted with 3 replications in a completely randomized design. Seeds were subjected to different treatments including various levels of GA3, H2SO4, soaking with water and chilling. Germination of Teucrium polium increased with different concentrations of GA3. Percentage germination Maximum and rate was obtained at concentrations of 250, 1500 ppm (72h GA3 and combination of GA3 (1500ppm and chilling (5 ºC for a period of 14 days. GA3 (500ppm increased germination percentage but not germination rate. Soaking with water broke dormancy and induced 32% seed germination of Teucrium polium, but H2SO4, freezing (-10 ºC and combination of both treatments had no effect on dormancy.

  14. physiological mechanisms for potato dormancy release

    African Journals Online (AJOL)

    ACSS

    of deep dormancy, during which potato seeds do not germinate after ... dormancy period and sprouting behaviour are major criteria ... develop once sprouting begins; such as changes ...... an example of plant information processing. Plant Cell ...

  15. A Proteomic Signature of Dormancy in the Actinobacterium Micrococcus luteus.

    Science.gov (United States)

    Mali, Sujina; Mitchell, Morgan; Havis, Spencer; Bodunrin, Abiodun; Rangel, Jonathan; Olson, Gabriella; Widger, William R; Bark, Steven J

    2017-07-15

    Dormancy is a protective state in which diverse bacteria, including Mycobacterium tuberculosis , Staphylococcus aureus , Treponema pallidum (syphilis), and Borrelia burgdorferi (Lyme disease), curtail metabolic activity to survive external stresses, including antibiotics. Evidence suggests dormancy consists of a continuum of interrelated states, including viable but nonculturable (VBNC) and persistence states. VBNC and persistence contribute to antibiotic tolerance, reemergence from latent infections, and even quorum sensing and biofilm formation. Previous studies indicate that the protein mechanisms regulating persistence and VBNC states are not well understood. We have queried the VBNC state of Micrococcus luteus NCTC 2665 (MI-2665) by quantitative proteomics combining gel electrophoresis, high-performance liquid chromatography, and tandem mass spectrometry to elucidate some of these mechanisms. MI-2665 is a nonpathogenic actinobacterium containing a small (2.5-Mb), high-GC-content genome which exhibits a well-defined VBNC state induced by nutrient deprivation. The MI-2665 VBNC state demonstrated a loss of protein diversity accompanied by increased levels of 18 proteins that are conserved across actinobacteria, 14 of which have not been previously identified in VNBC. These proteins implicate an anaplerotic strategy in the transition to VBNC, including changes in the glyoxylate shunt, redox and amino acid metabolism, and ribosomal regulatory processes. Our data suggest that MI-2665 is a viable model for dissecting the protein mechanisms underlying the VBNC stress response and provide the first protein-level signature of this state. We expect that this protein signature will enable future studies deciphering the protein mechanisms of dormancy and identify novel therapeutic strategies effective against antibiotic-tolerant bacterial infections. IMPORTANCE Dormancy is a protective state enabling bacteria to survive antibiotics, starvation, and the immune system

  16. Dim light at night disrupts the short-day response in Siberian hamsters.

    Science.gov (United States)

    Ikeno, Tomoko; Weil, Zachary M; Nelson, Randy J

    2014-02-01

    Photoperiodic regulation of physiology, morphology, and behavior is crucial for many animals to survive seasonally variable conditions unfavorable for reproduction and survival. The photoperiodic response in mammals is mediated by nocturnal secretion of melatonin under the control of a circadian clock. However, artificial light at night caused by recent urbanization may disrupt the circadian clock, as well as the photoperiodic response by blunting melatonin secretion. Here we examined the effect of dim light at night (dLAN) (5lux of light during the dark phase) on locomotor activity rhythms and short-day regulation of reproduction, body mass, pelage properties, and immune responses of male Siberian hamsters. Short-day animals reduced gonadal and body mass, decreased spermatid nuclei and sperm numbers, molted to a whiter pelage, and increased pelage density compared to long-day animals. However, animals that experienced short days with dLAN did not show these short-day responses. Moreover, short-day specific immune responses were altered in dLAN conditions. The nocturnal activity pattern was blunted in dLAN hamsters, consistent with the observation that dLAN changed expression of the circadian clock gene, Period1. In addition, we demonstrated that expression levels of genes implicated in the photoperiodic response, Mel-1a melatonin receptor, Eyes absent 3, thyroid stimulating hormone receptor, gonadotropin-releasing hormone, and gonadotropin-inhibitory hormone, were higher in dLAN animals than those in short-day animals. These results suggest that dLAN disturbs the circadian clock function and affects the molecular mechanisms of the photoperiodic response. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Chilling of Dormant Buds Hyperinduces FLOWERING LOCUS T and Recruits GA-Inducible 1,3-β-Glucanases to Reopen Signal Conduits and Release Dormancy in Populus[W][OA

    Science.gov (United States)

    Rinne, Päivi L.H.; Welling, Annikki; Vahala, Jorma; Ripel, Linda; Ruonala, Raili; Kangasjärvi, Jaakko; van der Schoot, Christiaan

    2011-01-01

    In trees, production of intercellular signals and accessibility of signal conduits jointly govern dormancy cycling at the shoot apex. We identified 10 putative cell wall 1,3-β-glucanase genes (glucan hydrolase family 17 [GH17]) in Populus that could turn over 1,3-β-glucan (callose) at pores and plasmodesmata (PD) and investigated their regulation in relation to FT and CENL1 expression. The 10 genes encode orthologs of Arabidopsis thaliana BG_ppap, a PD-associated glycosylphosphatidylinositol (GPI) lipid-anchored protein, the Arabidopsis PD callose binding protein PDCB, and a birch (Betula pendula) putative lipid body (LB) protein. We found that these genes were differentially regulated by photoperiod, by chilling (5°C), and by feeding of gibberellins GA3 and GA4. GA3 feeding upregulated all LB-associated GH17s, whereas GA4 upregulated most GH17s with a GPI anchor and/or callose binding motif, but only GA4 induced true bud burst. Chilling upregulated a number of GA biosynthesis and signaling genes as well as FT, but not CENL1, while the reverse was true for both GA3 and GA4. Collectively, the results suggest a model for dormancy release in which chilling induces FT and both GPI lipid-anchored and GA3-inducible GH17s to reopen signaling conduits in the embryonic shoot. When temperatures rise, the reopened conduits enable movement of FT and CENL1 to their targets, where they drive bud burst, shoot elongation, and morphogenesis. PMID:21282527

  18. PHOTOPERIODIC HISTORY AFFECTS THE CRITICAL DAYLENGTH OF THE SHORT-DAY PLANT ACROSYMPHYTON-PURPURIFERUM (RHODOPHYTA)

    NARCIS (Netherlands)

    BREEMAN, AM

    The crustose tetrasporophyte of the red alga Acrosymphyton purpuriferum is a qualitative short-day plant in the formation of its tetrasporangia. The critical daylength for the response was determined in plants precultured in various long-day regimes [20:4, 18:6, 16:8 and 14:10 (L:D, h)]. There was a

  19. Study on dormancy in Gladiolus

    International Nuclear Information System (INIS)

    Pandey, R.N.

    1980-01-01

    An attempt was made to break the dormancy of the corms and cormels of Gladiolus var. 'Scarlet' by conventional treatments such as temperature, chemical and hormonal and an unconventional treatment like ionizing radiation. The radiation treatment included the presowing irradiation of corms and cormels with different doses of 60 Co-gamma rays. Lower doses (500 to 2000 R) proved stimulatory for sprouting only when the corms had undergone some post-irradiation storage. Sprouting of cormels was stimulated by 1 KR and inhibited gradually by higher doses. The effect of 1 KR and 10 KR on various physiological parameters such as respiration, changes in starch, sugars and amylase activity was studied during the post-irradiation storage of the cormels in the moist sand. In general, while the irradiation by 1 KR resulted in an increase in oxygen uptake, 10 KR dose decreased it. Total amylase activity was inhibited by irradiation at both the doses. This inhibitory effect was over by two weeks in 1 KR-irradiated lot and 4 weeks in 10 KR-irradiated lot. Slight stimulation in the activity of alpha amylase and of total amylase was observed at later stages in 1 KR-irradiated lot. Beta amylase activity was inhibited by irradiation at both the doses. Changes in starch content of irradiated lots showed both increase and decrease at times. Changes in total sugars content in treated lots followed a pattern as in control, except that the magnitude of the changes differed. The pattern of changes in reducing and non-reducing sugars was almost similar qualitatively in irradiated and control cormels. Thus, radiation induced promotion and inhibition of sprouting could be generally and respectively attributed to improved and lowered availability of simpler carbohydrates for developing roots and shoots. (auth.)

  20. Temperature-mediated changes in seed dormancy and light requirement for Penstemon palmeri (Scrophulariaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Kitchen, S.G.; Meyer, S.E. (Dept of Agriculture, Provo, UT (United States))

    1992-03-01

    Penstemon palmeri is a short-lived perennial herb colonizing disturbed sites in semiarid habitats in the western US. In this study seed was harvested from six native and four seeded populations during two consecutive years. In laboratory germination trials at constant 15C, considerable between-lot variation in primary dormancy and light requirement was observed. Four weeks of moist chilling (1C) induced secondary dormancy at 15C. Cold-induced secondary dormancy was reversed by one week of dark incubation at 30C. This warm incubation treatment also reduced the light requirement of unchilled, after-ripened seed. Fluctuations in dormancy and light requirement of buried seeds have been linked to seasonal changes in soil temperature. Penstemon palmeri germination responses to temperature appear to be similar to those of facultative winter annuals.

  1. Cellular Adhesion Promotes Prostate Cancer Cells Escape from Dormancy.

    Science.gov (United States)

    Ruppender, Nazanin; Larson, Sandy; Lakely, Bryce; Kollath, Lori; Brown, Lisha; Coleman, Ilsa; Coleman, Roger; Nguyen, Holly; Nelson, Peter S; Corey, Eva; Snyder, Linda A; Vessella, Robert L; Morrissey, Colm; Lam, Hung-Ming

    2015-01-01

    Dissemination of prostate cancer (PCa) cells to the bone marrow is an early event in the disease process. In some patients, disseminated tumor cells (DTC) proliferate to form active metastases after a prolonged period of undetectable disease known as tumor dormancy. Identifying mechanisms of PCa dormancy and reactivation remain a challenge partly due to the lack of in vitro models. Here, we characterized in vitro PCa dormancy-reactivation by inducing cells from three patient-derived xenograft (PDX) lines to proliferate through tumor cell contact with each other and with bone marrow stroma. Proliferating PCa cells demonstrated tumor cell-cell contact and integrin clustering by immunofluorescence. Global gene expression analyses on proliferating cells cultured on bone marrow stroma revealed a downregulation of TGFB2 in all of the three proliferating PCa PDX lines when compared to their non-proliferating counterparts. Furthermore, constitutive activation of myosin light chain kinase (MLCK), a downstream effector of integrin-beta1 and TGF-beta2, in non-proliferating cells promoted cell proliferation. This cell proliferation was associated with an upregulation of CDK6 and a downregulation of E2F4. Taken together, our data provide the first clinically relevant in vitro model to support cellular adhesion and downregulation of TGFB2 as a potential mechanism by which PCa cells may escape from dormancy. Targeting the TGF-beta2-associated mechanism could provide novel opportunities to prevent lethal PCa metastasis.

  2. Blackout cloth for dormancy induction

    Science.gov (United States)

    Tom Jopson

    2007-01-01

    The use of blackout cloth to create long night photoperiods for the induction of dormancy in certain conifer species has been an established practice for a long time. Its use was suggested by Tinus and McDonald (1979) as an effective technique, and the practice has been commonly used in Canadian forest nurseries for a number of years. Cal-Forest Nursery installed its...

  3. Flower formation in the short-day plant Kalanchoe by grafting with a long-day and a short-long-day Echeveria

    Energy Technology Data Exchange (ETDEWEB)

    Zeevaart, J.A.D.

    1978-01-01

    Flower formation was induced in the short-day plant Kalanchoe blossfeldiana Poellnitz under long-day conditions by grafting with flowering shoots of the short-long-day plant Echeveria harmsii (Rose) MacBr. and of the long-day plant Echeveria ''pulvoliver'' (E. pulvinata Rose x E. harmsii). Vegetative shoots from induced Echeveria plants failed to cause a flowering response in Kalanchoe. The presence of flowering and vegetative shoots side by side on induced Echeveria plants provides evidence for physiological chimeras in this genus.

  4. Regulation of seasonal patterns in seed dormancy

    NARCIS (Netherlands)

    Derkx, M.P.M.

    1993-01-01

    Buried seeds of many wild species pass annually through a pattern of induction and release of dormancy. These reversible changes in dormancy may be repeated for numbers of years when seeds are deprived from light and other germination-stimulating factors, and are a highly useful adaptation

  5. The role of phytochrome A and gibberellins in growth under long and short day conditions: Studies in hybrid aspen

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, M.E. [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Genetics and Plant Physiology

    2000-07-01

    This thesis addresses questions concerning the regulation of growth and, specifically, the cessation of growth in response to short days in deciduous tree species. The model tree used in the studies was hybrid aspen (Populus tremula L. x P. tremuloides Michx.). We have exploited the possibility of transforming this species to modulate the level of expression of target genes using over-expression and antisense techniques. The target genes in the studies were the photoreceptor phytochrome A (phyA) and gibberellin 20-oxidase (GA 20-oxidase), the latter being a highly regulated enzyme involved in the biosynthesis of gibberellins (GAs). The photoreceptor phyA has been implicated in photoperiodic regulation of growth, while GAs may regulate the physiological response further downstream. The endogenous expression of these genes has been investigated in parallel with studies of various plants with ectopic and reduced levels of expression. The main focus has been on the early stages of induction of growth cessation and its physiological and molecular mechanisms. Studies of hybrid aspen plants with an increased or reduced expression of phyA, show this receptor to mediate the photoperiodic regulation of growth. Plants with ectopic expression could not stop growing despite drastically shortened photoperiods, while the antisense plants showed the reverse phenotype, with a higher sensitivity resulting in earlier cessation of growth. The role of GAs in growth inhibition was also addressed using plants with a reduction in GA levels. These plants showed early cessation of growth and dormancy, and thus an increased sensitivity toward daylength. Conversely, plants with increased rates of GA biosynthesis showed increased growth and stopped growing much later. Furthermore, increases in GA biosynthesis, resulting in high levels of GAs have a major impact on growth. Plants with high GA levels have increased elongation and diameter growth, due to higher rates of cell production in the

  6. Metabolomics reveals an involvement of pantothenate for male production responding to the short-day stimulus in the water flea, Daphnia pulex.

    Science.gov (United States)

    Toyota, Kenji; Gavin, Alex; Miyagawa, Shinichi; Viant, Mark R; Iguchi, Taisen

    2016-04-26

    Under favorable conditions, the micro-crustacean Daphnia pulex produces female offspring by parthenogenesis, whereas under unfavorable conditions, they produce male offspring to induce sexual reproduction (environmental sex determination: ESD). We recently established a suitable system for ESD studies using D. pulex WTN6 strain, in which the sex of the offspring can be regulated by alterations in day-length; long-day and short-day conditions can induce female and male offspring, respectively. Taking advantage of this system, we have already demonstrated that methyl farnesoate (MF) synthesis is necessary for male offspring production, and identified ionotropic glutamate receptors as an upstream regulator of MF signaling. Despite these findings, the molecular mechanisms associated with MF signaling have not yet been well elucidated. In this study, we analyzed the whole metabolic profiles of mother daphnids reared under long-day (female-producing) and short-day (male-producing) conditions, and discovered that pantothenate (vitamin B5), a known precursor to coenzyme A, was significantly accumulated in response to the short-day condition. To confirm the innate role of pantothenate in D. pulex, this metabolite was administered to mother daphnids resulting in a significantly increased proportion of male offspring producing mothers. This study provides novel insights of the metabolic mechanisms of the ESD system in D. pulex.

  7. Bud dormancy in apple trees after thermal fluctuations

    Directory of Open Access Journals (Sweden)

    Rafael Anzanello

    2014-06-01

    Full Text Available The objective of this work was to evaluate the effect of heat waves on the evolution of bud dormancy, in apple trees with contrasting chilling requirements. Twigs of 'Castel Gala' and 'Royal Gala' were collected in orchards in Papanduva, state of Santa Catarina, Brazil, and were exposed to constant (3°C or alternating (3 and 15°C for 12/12 hours temperature, combined with zero, one or two days a week at 25°C. Two additional treatments were evaluated: constant temperature (3°C, with a heat wave of seven days at 25°C, in the beginning or in the middle of the experimental period. Periodically, part of the twigs was transferred to 25°C for daily budburst evaluation of apical and lateral buds. Endodormancy (dormancy induced by cold was overcome with less than 330 chilling hours (CH of constant cold in 'Castel Gala' and less than 618 CH in 'Royal Gala'. A daily 15°C-temperature cycle did not affect the endodormancy process. Heat waves during endodormancy resulted in an increased CH to achieve bud requirements. The negative effect of high temperature depended on the lasting of this condition. Chilling was partly cancelled during dormancy when the heat wave lasted 36 continuous hours or more. Therefore, budburst prediction models need adjustments, mainly for regions with mild and irregular winters, such as those of Southern Brazil.

  8. Short-day treatment alters Douglas-fir seedling dehardening and transplant root proliferation at varying rhizosphere temperatures

    Science.gov (United States)

    Douglass F. Jacobs; Anthony S. Davis; BArrett C. Wilson; R. Kasten Dumroese; Rosa C. Goodman; K. Francis Salifu

    2008-01-01

    We tested effects of shortened day length during nursery culture on Douglis-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) seedling development at dormancy release. Seedlings from a 42 N source were grown either under ambient photoperiods (long-day (LD)) or with a 28 day period of 9 h light: 15 h dark photoperiods (short...

  9. Inheritance of late flowering in natural variants of soybean cultivars under short-day conditions

    Directory of Open Access Journals (Sweden)

    Valeria Carpentieri-Pipolo

    2014-10-01

    Full Text Available The objective of this work was to determine the inheritance of the long juvenile period trait in natural variants of the Doko, BR 9 (Savana, Davis, Embrapa 1 (IAS 5RC, and BR 16 soybean cultivars. Complete diallel crosses were made between the Doko and BR 16 cultivars and their variants. A 3:1 segregation ratio was observed in the F2 populations of the 'Doko' x Doko-18T, 'Doko' x Doko-Milionária, 'Davis' x São Carlos, and 'BR 9 (Savana' x MABR92-836 (Savanão crosses, indicating that the long juvenile period trait is controlled by a pair of recessive genes. The difference in late flowering between the Doko cultivar and both of its variants was caused by a recessive spontaneous mutation at the same genetic locus. However, the variants Doko-18T and Doko-Milionária are identical mutants that share a pair of genes that control the long juvenile period under short-day conditions. These mutants can be used in breeding programs to develop cultivars adapted to low-latitude tropical regions.

  10. Map-Based Cloning of Seed Dormancy1-2 Identified a Gibberellin Synthesis Gene Regulating the Development of Endosperm-Imposed Dormancy in Rice.

    Science.gov (United States)

    Ye, Heng; Feng, Jiuhuan; Zhang, Lihua; Zhang, Jinfeng; Mispan, Muhamad S; Cao, Zhuanqin; Beighley, Donn H; Yang, Jianchang; Gu, Xing-You

    2015-11-01

    Natural variation in seed dormancy is controlled by multiple genes mapped as quantitative trait loci in major crop or model plants. This research aimed to clone and characterize the Seed Dormancy1-2 (qSD1-2) locus associated with endosperm-imposed dormancy and plant height in rice (Oryza sativa). qSD1-2 was delimited to a 20-kb region, which contains OsGA20ox2 and had an additive effect on germination. Naturally occurring or induced loss-of-function mutations of the gibberellin (GA) synthesis gene enhanced seed dormancy and also reduced plant height. Expression of this gene in seeds (including endospermic cells) during early development increased GA accumulation to promote tissue morphogenesis and maturation programs. The mutant allele prevalent in semidwarf cultivars reduced the seed GA content by up to 2-fold at the early stage, which decelerated tissue morphogenesis including endosperm cell differentiation, delayed abscisic acid accumulation by a shift in the temporal distribution pattern, and postponed dehydration, physiological maturity, and germinability development. As the endosperm of developing seeds dominates the moisture equilibrium and desiccation status of the embryo in cereal crops, qSD1-2 is proposed to control primary dormancy by a GA-regulated dehydration mechanism. Allelic distribution of OsGA20ox2, the rice Green Revolution gene, was associated with the indica and japonica subspeciation. However, this research provided no evidence that the primitive indica- and common japonica-specific alleles at the presumably domestication-related locus functionally differentiate in plant height and seed dormancy. Thus, the evolutionary mechanism of this agriculturally important gene remains open for discussion. © 2015 American Society of Plant Biologists. All Rights Reserved.

  11. Map-Based Cloning of Seed Dormancy1-2 Identified a Gibberellin Synthesis Gene Regulating the Development of Endosperm-Imposed Dormancy in Rice1

    Science.gov (United States)

    Ye, Heng; Feng, Jiuhuan; Zhang, Lihua; Zhang, Jinfeng; Mispan, Muhamad S.; Cao, Zhuanqin; Beighley, Donn H.; Yang, Jianchang; Gu, Xing-You

    2015-01-01

    Natural variation in seed dormancy is controlled by multiple genes mapped as quantitative trait loci in major crop or model plants. This research aimed to clone and characterize the Seed Dormancy1-2 (qSD1-2) locus associated with endosperm-imposed dormancy and plant height in rice (Oryza sativa). qSD1-2 was delimited to a 20-kb region, which contains OsGA20ox2 and had an additive effect on germination. Naturally occurring or induced loss-of-function mutations of the gibberellin (GA) synthesis gene enhanced seed dormancy and also reduced plant height. Expression of this gene in seeds (including endospermic cells) during early development increased GA accumulation to promote tissue morphogenesis and maturation programs. The mutant allele prevalent in semidwarf cultivars reduced the seed GA content by up to 2-fold at the early stage, which decelerated tissue morphogenesis including endosperm cell differentiation, delayed abscisic acid accumulation by a shift in the temporal distribution pattern, and postponed dehydration, physiological maturity, and germinability development. As the endosperm of developing seeds dominates the moisture equilibrium and desiccation status of the embryo in cereal crops, qSD1-2 is proposed to control primary dormancy by a GA-regulated dehydration mechanism. Allelic distribution of OsGA20ox2, the rice Green Revolution gene, was associated with the indica and japonica subspeciation. However, this research provided no evidence that the primitive indica- and common japonica-specific alleles at the presumably domestication-related locus functionally differentiate in plant height and seed dormancy. Thus, the evolutionary mechanism of this agriculturally important gene remains open for discussion. PMID:26373662

  12. FEATURES OF THE SEED DORMANCY IN UMBELLIFER CROPS CAUSED BY VARIOUS FACTORS

    Directory of Open Access Journals (Sweden)

    D. N. Baleev

    2017-01-01

    Full Text Available Experiments were carried out at FGBNU VNIIO in 20112016. The aim of the study was to analyze the influence of different types of organic dormancy caused by various factors on seed quality of some representatives of umbellifer crops. The objects of the study were seeds: parsnip ‘Kulinar’ (Pastinaca sativa L.; carrot ‘Rogneda’ (Daucus carrota L.; root parsley ‘Ljubasha’ (Petroselinum crispum (Mill. Nyman ex A.W. Hill.; root celery ‘Kupidon’ (Apium graveolens L.; coriander ‘Yantar’ (Coriandrum sativum L. and dill ‘Kentavr’ (Anethum graveolens L.. In all seeds studied, the speed of embryo growth was decreased by 30% or0.03 mma day. Under influence of the induced dormancy caused by incubation in extract from dill seeds, the speed of embryo growth in all species was decreased by 94-97% on average. The process of germination of just picked seeds in all crops studied showed itself in reduction of germinated seed number by 54% as compared with control variant. Under the effect of incubation at high temperature the seeds of parsnip and root celery didn’t germinate, whereas the germination in the seeds of coriander, root parsley and carrot was decreased by 51%, 47% and 46%, respectively as compared with control. There is no germination observed in parsnip, carrot, root celery and coriander under influence of induced dormancy caused by incubation in extract from dill seeds. In this case, the germination of seeds of root parsley and dill was 8.1% and 15%, respectively. The Pearson correlation between the speed of embryo growth and percent of seed germination showed the significant and positive relationship in the range 0.706-0.952. Analysis of variance (ANOVA showed that induced by temperature or allelopathic dormancy had impact on the speed of embryo’s growth in the crops studied, where factor effect was 89-86% depending on type of dormancy. Analysis of variance between the factors of dormancy and germination revealed that all

  13. ABA crosstalk with ethylene and nitric oxide in seed dormancy and germination

    Directory of Open Access Journals (Sweden)

    Erwann eArc

    2013-03-01

    Full Text Available Dormancy is an adaptive trait that enables seed germination to coincide with favorable environmental conditions. It has been clearly demonstrated that dormancy is induced by abscisic acid (ABA during seed development on the mother plant. After seed dispersal, germination is preceded by a decline in ABA in imbibed seeds, which results from ABA catabolism through 8’-hydroxylation. The hormonal balance between ABA and gibberellins (GAs has been shown to act as an integrator of environmental cues to maintain dormancy or activate germination. The interplay of ABA with other endogenous signals is however less documented. In numerous species, ethylene counteracts ABA signaling pathways and induces germination. In Brassicaceae seeds, ethylene prevents the inhibitory effects of ABA on endosperm cap weakening, thereby facilitating endosperm rupture and radicle emergence. Moreover, enhanced seed dormancy in Arabidopsis ethylene-insensitive mutants results from greater ABA sensitivity. Conversely, ABA limits ethylene action by down-regulating its biosynthesis. Nitric oxide (NO has been proposed as a common actor in the ABA and ethylene crosstalk in seed. Indeed, convergent evidence indicates that NO is produced rapidly after seed imbibition and promotes germination by inducing the expression of the ABA 8’-hydroxylase gene, CYP707A2, and stimulating ethylene production. The role of NO and other nitrogen-containing compounds, such as nitrate, in seed dormancy breakage and germination stimulation has been reported in several species. This review will describe our current knowledge of ABA crosstalk with ethylene and NO, both volatile compounds that have been shown to counteract ABA action in seeds and to improve dormancy release and germination.

  14. 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

  15. Effects of temperature and photoperiod on postponing bermudagrass (Cynodon dactylon [L.] Pers.) turf dormancy.

    Science.gov (United States)

    Esmaili, Somayeh; Salehi, Hassan

    2012-06-15

    Growth chamber and field experiments were carried out to determine the effects of extended photoperiod under low and freezing temperatures on bermudagrass turf dormancy at Bajgah, in the southern part of Iran. The experiment in the growth chamber was conducted with four temperature regimes (15, 7.5, 0 and -7.5°C) and three light durations (8, 12 and 16h) in a completely randomized design with four replications. The field study was conducted in two consecutive years (2008-2009) with three light durations (8, 12 and 16h) in months with natural short day length and arranged in a randomized complete blocks design with three replications. Results in both experiments showed that decreasing temperature and photoperiod decreased verdure fresh and dry weight, shoot height, tiller density, leaf area and chlorophyll and relative water contents (RWC). However, rooting depth and fresh weight of roots increased in the growth chamber. Decreasing the temperature and light duration increased electrolyte leakage and proline content. Reducing sugars increased with decreasing temperature and declined with lowering light duration in both shoots and roots. Starch content of both shoots and roots showed an adverse trend compared to reducing sugars; starch content increased in both shoots and roots in all treatments by shortening the photoperiod. Practically, the problem of bermudagrass turf's dormancy could be solved via increasing the photoperiod in months with short day lengths. This treatment would be efficient and useful for turfgrass managers to apply in landscapes and stadiums. Copyright © 2012 Elsevier GmbH. All rights reserved.

  16. Control of seed dormancy in Nicotiana plumbaginifolia: post-imbibition abscisic acid synthesis imposes dormancy maintenance.

    Science.gov (United States)

    Grappin, P; Bouinot, D; Sotta, B; Miginiac, E; Jullien, M

    2000-01-01

    The physiological characteristics of seed dormancy in Nicotiana plumbaginifolia Viv. are described. The level of seed dormancy is defined by the delay in seed germination (i.e the time required prior to germination) under favourable environmental conditions. A wild-type line shows a clear primary dormancy, which is suppressed by afterripening, whereas an abscisic acid (ABA)-deficient mutant shows a non-dormant phenotype. We have investigated the role of ABA and gibberellic acid (GA(3)) in the control of dormancy maintenance or breakage during imbibition in suitable conditions. It was found that fluridone, a carotenoid biosynthesis inhibitor, is almost as efficient as GA(3) in breaking dormancy. Dry dormant seeds contained more ABA than dry afterripened seeds and, during early imbibition, there was an accumulation of ABA in dormant seeds, but not in afterripened seeds. In addition, fluridone and exogenous GA(3) inhibited the accumulation of ABA in imbibed dormant seeds. This reveals an important role for ABA synthesis in dormancy maintenance in imbibed seeds.

  17. An increase in pectin methyl esterase activity accompanies dormancy breakage and germination of yellow cedar seeds.

    Science.gov (United States)

    Ren, C; Kermode, A R

    2000-09-01

    Pectin methyl esterase (PME) (EC 3.1.1.11) catalyzes the hydrolysis of methylester groups of cell wall pectins. We investigated the role of this enzyme in dormancy termination and germination of yellow cedar (Chamaecyparis nootkatensis [D. Don] Spach) seeds. PME activity was not detected in dormant seeds of yellow cedar but was induced and gradually increased during moist chilling; high activity coincided with dormancy breakage and germination. PME activity was positively correlated to the degree of dormancy breakage of yellow cedar seeds. The enzyme produced in different seed parts and in seeds at different times during moist chilling, germination, and early post-germinative growth consisted of two isoforms, both basic with isoelectric points of 8.7 and 8.9 and the same molecular mass of 62 kD. The pH optimum for the enzyme was between 7.4 and 8.4. In intact yellow cedar seeds, activities of the two basic isoforms of PME that were induced in embryos and in megagametophytes following dormancy breakage were significantly suppressed by abscisic acid. Gibberellic acid had a stimulatory effect on the activities of these isoforms in embryos and megagametophytes of intact seeds at the germinative stage. We hypothesize that PME plays a role in weakening of the megagametophyte, allowing radicle emergence and the completion of germination.

  18. TBK1 Regulates Prostate Cancer Dormancy through mTOR Inhibition

    Directory of Open Access Journals (Sweden)

    Jin Koo Kim

    2013-09-01

    Full Text Available The mechanisms that regulate hematopoietic stem cell (HSC dormancy and self-renewal are well established and are largely dependent on signals emanating from the HSC niche. Recently, we found that prostate cancer (PCa cells target the HSC niche in mouse bone marrow (BM during metastasis. Little is known, however, as to how the HSC niche may regulate dormancy in cancer cells. In this study, we investigated the effects of TANK binding kinase 1 (TBK1 on PCa dormancy in the BM niche. We found that binding with niche osteoblasts induces the expression of TBK1 in PCa cells PC3 and C4-2B. Interestingly, TBK1 interacts with mammalian target of rapamycin (mTOR and inhibits its function. Rapamycin, an mTOR inhibitor, induces cell cycle arrest of PCa cells and enhances chemotherapeutic resistance of PCa cells. As a result, the knockdown of TBK1 decreases PCa stem-like cells and drug resistance in vitro and in vivo. Taken together, these results strongly indicate that TBK1 plays an important role in the dormancy and drug resistance of PCa.

  19. Inheritance of fresh seed dormancy in groundnut

    African Journals Online (AJOL)

    SERVER

    2008-02-19

    Feb 19, 2008 ... Seed dormancy has been defined as the failure of an intact, viable seed to ... expected ratio of 3 dormant : 1 non-dormant seeds in F2 generations of crosses of ICGV 87378 and ICGV ... ICGV 87378 x ICGV 86158. 163. 0. 163.

  20. Differential dormancy of co-occurring copepods

    Science.gov (United States)

    Ohman, Mark D.; Drits, Aleksandr V.; Elizabeth Clarke, M.; Plourde, Stéphane

    1998-08-01

    Four species of planktonic calanoid copepods that co-occur in the California Current System ( Eucalanus californicus Johnson, Rhincalanus nasutus Giesbrecht, Calanus pacificus californicus Brodsky, and Metridia pacifica Brodsky) were investigated for evidence of seasonal dormancy in the San Diego Trough. Indices used to differentiate actively growing from dormant animals included developmental stage structure and vertical distribution; activity of aerobic metabolic enzymes (Citrate Synthase and the Electron Transfer System complex); investment in depot lipids (wax esters and triacylglycerols); in situ grazing activity from gut fluorescence; and egg production rates in simulated in situ conditions. None of the 4 species exhibited a canonical calanoid pattern of winter dormancy - i.e., synchronous developmental arrest as copepodid stage V, descent into deep waters, reduced metabolism, and lack of winter reproduction. Instead, Calanus pacificus californicus has a biphasic life history in this region, with an actively reproducing segment of the population in surface waters overlying a deep dormant segment in winter. Eucalanus californicus is dormant as both adult females and copepodid V's, although winter females respond relatively rapidly to elevated food and temperature conditions; they begin feeding and producing eggs within 2-3 days. Rhincalanus nasutus appears to enter dormancy as adult females, although the evidence is equivocal. Metridia pacifica shows no evidence of dormancy, with sustained active feeding, diel vertical migration behavior, and elevated activity of metabolic enzymes in December as well as in June. The four species also differ markedly in water content, classes of storage lipids, and specific activity of Citrate Synthase. These results suggest that copepod dormancy traits and structural composition reflect diverse adaptations to regional environmental conditions rather than a uniform, canonical series of traits that remain invariant among taxa

  1. Humidity-regulated dormancy onset in the Fabaceae: a conceptual model and its ecological implications for the Australian wattle Acacia saligna

    Science.gov (United States)

    Tozer, Mark G.; Ooi, Mark K. J.

    2014-01-01

    Background and aims Seed dormancy enhances fitness by preventing seeds from germinating when the probability of seedling survival and recruitment is low. The onset of physical dormancy is sensitive to humidity during ripening; however, the implications of this mechanism for seed bank dynamics have not been quantified. This study proposes a model that describes how humidity-regulated dormancy onset may control the accumulation of a dormant seed bank, and seed experiments are conducted to calibrate the model for an Australian Fabaceae, Acacia saligna. The model is used to investigate the impact of climate on seed dormancy and to forecast the ecological implications of human-induced climate change. Methods The relationship between relative humidity and dormancy onset was quantified under laboratory conditions by exposing freshly matured non-dormant seeds to constant humidity levels for fixed durations. The model was field-calibrated by measuring the response of seeds exposed to naturally fluctuating humidity. The model was applied to 3-hourly records of humidity spanning the period 1972–2007 in order to estimate both temporal variability in dormancy and spatial variability attributable to climatic differences among populations. Climate change models were used to project future changes in dormancy onset. Key Results A sigmoidal relationship exists between dormancy and humidity under both laboratory and field conditions. Seeds ripened under field conditions became dormant following very short exposure to low humidity (<20 %). Prolonged exposure at higher humidity did not increase dormancy significantly. It is predicted that populations growing in a temperate climate produce 33–55 % fewer dormant seeds than those in a Mediterranean climate; however, dormancy in temperate populations is predicted to increase as a result of climate change. Conclusions Humidity-regulated dormancy onset may explain observed variation in physical dormancy. The model offers a systematic

  2. Humidity-regulated dormancy onset in the Fabaceae: a conceptual model and its ecological implications for the Australian wattle Acacia saligna.

    Science.gov (United States)

    Tozer, Mark G; Ooi, Mark K J

    2014-09-01

    Seed dormancy enhances fitness by preventing seeds from germinating when the probability of seedling survival and recruitment is low. The onset of physical dormancy is sensitive to humidity during ripening; however, the implications of this mechanism for seed bank dynamics have not been quantified. This study proposes a model that describes how humidity-regulated dormancy onset may control the accumulation of a dormant seed bank, and seed experiments are conducted to calibrate the model for an Australian Fabaceae, Acacia saligna. The model is used to investigate the impact of climate on seed dormancy and to forecast the ecological implications of human-induced climate change. The relationship between relative humidity and dormancy onset was quantified under laboratory conditions by exposing freshly matured non-dormant seeds to constant humidity levels for fixed durations. The model was field-calibrated by measuring the response of seeds exposed to naturally fluctuating humidity. The model was applied to 3-hourly records of humidity spanning the period 1972-2007 in order to estimate both temporal variability in dormancy and spatial variability attributable to climatic differences among populations. Climate change models were used to project future changes in dormancy onset. A sigmoidal relationship exists between dormancy and humidity under both laboratory and field conditions. Seeds ripened under field conditions became dormant following very short exposure to low humidity (humidity did not increase dormancy significantly. It is predicted that populations growing in a temperate climate produce 33-55 % fewer dormant seeds than those in a Mediterranean climate; however, dormancy in temperate populations is predicted to increase as a result of climate change. Humidity-regulated dormancy onset may explain observed variation in physical dormancy. The model offers a systematic approach to modelling this variation in population studies. Forecast changes in climate have

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

    Science.gov (United States)

    Pawłowski, Tomasz A

    2009-05-04

    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. 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. 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 state to germination. Seed dormancy breaking involves

  4. 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

  5. Biological methods for assessment of budbreak in apple trees for modeling dormancy

    Directory of Open Access Journals (Sweden)

    Rafael Anzanello

    2014-06-01

    Full Text Available A biological method was developed to evaluate the dormancy state of apple buds under controlled conditions. Cuttings (20-25 cm long of ‘Castel Gala’ and ‘Royal Gala’ were sampled during the winter period, evaluating different cold and heat regimes to induce budbreak. Contrasts were tested in plant material processing (single node x intact cuttings, cold storage method to break dormancy in incubator chambers (planted in pots with floral foam x wrapped in plastic film, vertically or horizontally and budbreak method in plant growth chambers (base immersed in water x planted in floral foam. Intact cuttings stored vertically in the cold represented better the natural interactions between buds than single node cuttings. Budbreak of lateral buds was strongly influenced by apical dominance. Wrapping cuttings in plastic film optimized internal space usage in the incubators and the number of evaluated buds, compared to planting cuttings in pots. During the warm period in the growth chambers, intact cuttings on floral foam resulted in better bud preservation and survival throughout the evaluation period, compared to cuttings with bases immersed in water. The most suitable conditions to evaluate dormancy evolution in apple buds used plastic-wrapped intact cuttings stored vertically during the cold period, with budbreak evaluation in the warm period after planting the cuttings in floral foam. Standardization of methodology helps to obtain better results in the development of physiological models of dormancy.

  6. Gladiolus hybridus ABSCISIC ACID INSENSITIVE 5 (GhABI5) is an important transcription factor in ABA signaling that can enhance Gladiolus corm dormancy and Arabidopsis seed dormancy.

    Science.gov (United States)

    Wu, Jian; Seng, Shanshan; Sui, Juanjuan; Vonapartis, Eliana; Luo, Xian; Gong, Benhe; Liu, Chen; Wu, Chenyu; Liu, Chao; Zhang, Fengqin; He, Junna; Yi, Mingfang

    2015-01-01

    The phytohormone abscisic acid (ABA) regulates plant development and is crucial for abiotic stress response. In this study, cold storage contributes to reducing endogenous ABA content, resulting in dormancy breaking of Gladiolus. The ABA inhibitor fluridone also promotes germination, suggesting that ABA is an important hormone that regulates corm dormancy. Here, we report the identification and functional characterization of the Gladiolus ABI5 homolog (GhABI5), which is a basic leucine zipper motif transcriptional factor (TF). GhABI5 is expressed in dormant vegetative organs (corm, cormel, and stolon) as well as in reproductive organs (stamen), and it is up-regulated by ABA or drought. Complementation analysis reveals that GhABI5 rescues the ABA insensitivity of abi5-3 during seed germination and induces the expression of downstream ABA response genes in Arabidopsis thaliana (EM1, EM6, and RD29B). Down-regulation of GhABI5 in dormant cormels via virus induced gene silence promotes sprouting and reduces the expression of downstream genes (GhLEA and GhRD29B). The results of this study reveal that GhABI5 regulates bud dormancy (vegetative organ) in Gladiolus in addition to its well-studied function in Arabidopsis seeds (reproductive organ).

  7. Gladiolus hybridus ABSCISIC ACID INSENSITIVE 5 (GhABI5 is an important transcription factor in ABA signaling that can enhance Gladiolus corm dormancy and Arabidopsis seed dormancy.

    Directory of Open Access Journals (Sweden)

    Jian eWu

    2015-11-01

    Full Text Available The phytohormone abscisic acid (ABA regulates plant development and is crucial for abiotic stress response. In this study, cold storage contributes to reducing endogenous ABA content, resulting in dormancy breaking of Gladiolus. The ABA inhibitor fluridone also promotes germination, suggesting that ABA is an important hormone that regulates corm dormancy. Here, we report the identification and functional characterization of the Gladiolus ABI5 homolog (GhABI5, which is a basic leucine zipper motif transcriptional factor (TF. GhABI5 is expressed in dormant vegetative organs (corm, cormel and stolon as well as in reproductive organs (stamen, and it is up-regulated by ABA or drought. Complementation analysis reveals that GhABI5 rescues the ABA insensitivity of abi5-3 during seed germination and induces the expression of downstream ABA response genes in Arabidopsis thaliana (EM1, EM6 and RD29B. Down-regulation of GhABI5 in dormant cormels via Virus Induced Gene Silence (VIGS promotes sprouting and reduces the expression of downstream genes (GhLEA and GhRD29B. The results of this study reveal that GhABI5 regulates bud dormancy (vegetative organ in Gladiolus in addition to its well-studied function in Arabidopsis seeds (reproductive organ.

  8. Dormancy Breaking in Ormosia arborea Seeds

    Directory of Open Access Journals (Sweden)

    Edilma Pereira Gonçalves

    2011-01-01

    Full Text Available Ormosia arborea is a tree species planted in urban areas and used to restore degraded areas. Its seeds are dormant and propagation is difficult. This study compares different dormancy breaking methods and physiological seed quality and seedling production. The seeds were germinated in sand in the laboratory of the Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil. The following dormancy breaking treatments were applied: control (intact seeds, 100°C water immersion; boiling water immersion followed by 24 hours of soaking; scarification with number 100 and number 50 sandpaper opposite from root emergence; sulfuric acid immersion for 1 hour, 50, 45, and 30 minutes. Seed immersion in 100°C and boiling water did not break the dormancy. The study species showed a greater vigor of seedling when its seeds were submitted to treatments associated with tegument rupturing by sandpaper or sulfuric acid. On the other hand, seed scarification with sulfuric acid for 1 hour, 50, 45, and 30 minutes or sandpaper favored seed germination and vigor.

  9. The C4 Model Grass Setaria Is a Short Day Plant with Secondary Long Day Genetic Regulation.

    Science.gov (United States)

    Doust, Andrew N; Mauro-Herrera, Margarita; Hodge, John G; Stromski, Jessica

    2017-01-01

    The effect of photoperiod (day:night ratio) on flowering time was investigated in the wild species, Setaria viridis , and in a set of recombinant inbred lines (RILs) derived from a cross between foxtail millet ( S. italica ) and its wild ancestor green foxtail ( S. viridis ). Photoperiods totaled 24 h, with three trials of 8:16, 12:12 and 16:8 light:dark hour regimes for the RIL population, and these plus 10:14 and 14:10 for the experiments with S. viridis alone. The response of S. viridis to light intensity as well as photoperiod was assessed by duplicating photoperiods at two light intensities (300 and 600 μmol.m -2 .s -1 ). In general, day lengths longer than 12 h delayed flowering time, although flowering time was also delayed in shorter day-lengths relative to the 12 h trial, even when daily flux in high intensity conditions exceeded that of the low intensity 12 h trial. Cluster analysis showed that the effect of photoperiod on flowering time differed between sets of RILs, with some being almost photoperiod insensitive and others being delayed with respect to the population as a whole in either short (8 or 12 h light) or long (16 h light) photoperiods. QTL results reveal a similar picture, with several major QTL colocalizing between the 8 and 12 h light trials, but with a partially different set of QTL identified in the 16 h trial. Major candidate genes for these QTL include several members of the PEBP protein family that includes Flowering Locus T (FT) homologs such as OsHd3a, OsRFT1, and ZCN8/12. Thus, Setaria is a short day plant (flowering quickest in short day conditions) whose flowering is delayed by long day lengths in a manner consistent with the responses of most other members of the grass family. However, the QTL results suggest that flowering time under long day conditions uses additional genetic pathways to those used under short day conditions.

  10. The C4 Model Grass Setaria Is a Short Day Plant with Secondary Long Day Genetic Regulation

    Directory of Open Access Journals (Sweden)

    Andrew N. Doust

    2017-07-01

    Full Text Available The effect of photoperiod (day:night ratio on flowering time was investigated in the wild species, Setaria viridis, and in a set of recombinant inbred lines (RILs derived from a cross between foxtail millet (S. italica and its wild ancestor green foxtail (S. viridis. Photoperiods totaled 24 h, with three trials of 8:16, 12:12 and 16:8 light:dark hour regimes for the RIL population, and these plus 10:14 and 14:10 for the experiments with S. viridis alone. The response of S. viridis to light intensity as well as photoperiod was assessed by duplicating photoperiods at two light intensities (300 and 600 μmol.m-2.s-1. In general, day lengths longer than 12 h delayed flowering time, although flowering time was also delayed in shorter day-lengths relative to the 12 h trial, even when daily flux in high intensity conditions exceeded that of the low intensity 12 h trial. Cluster analysis showed that the effect of photoperiod on flowering time differed between sets of RILs, with some being almost photoperiod insensitive and others being delayed with respect to the population as a whole in either short (8 or 12 h light or long (16 h light photoperiods. QTL results reveal a similar picture, with several major QTL colocalizing between the 8 and 12 h light trials, but with a partially different set of QTL identified in the 16 h trial. Major candidate genes for these QTL include several members of the PEBP protein family that includes Flowering Locus T (FT homologs such as OsHd3a, OsRFT1, and ZCN8/12. Thus, Setaria is a short day plant (flowering quickest in short day conditions whose flowering is delayed by long day lengths in a manner consistent with the responses of most other members of the grass family. However, the QTL results suggest that flowering time under long day conditions uses additional genetic pathways to those used under short day conditions.

  11. Evaluation of different methods to overcome in vitro seed dormancy ...

    African Journals Online (AJOL)

    SAM

    2014-09-03

    Sep 3, 2014 ... Seeds from yellow passion fruit (Passiflora edulis Sims) present dormancy imposed by the seed-coat. The present study aimed to evaluate some methods to overcome dormancy of seeds from P. edulis grown under in vitro conditions. The experimental design was completely randomized in factorial scheme ...

  12. Effects of different methods of breaking dormancy and seed ...

    African Journals Online (AJOL)

    Seed dormancy in palms, date palm inclusive have continued to be challenging especially when cultivating through seeds. This study evaluated different methods of breaking dormancy and seed germination rate in P. dactylifera. Using Completely Randomize Design, two varieties of P. dactylifera were treated with three ...

  13. Seed dormancy and germination - Emerging mechanisms and new hypotheses

    Directory of Open Access Journals (Sweden)

    Hiroyuki eNonogaki

    2014-05-01

    Full Text Available Seed dormancy has played a significant role in adaptation and evolution of seed plants. While its biological significance is clear, molecular mechanisms underlying seed dormancy induction, maintenance and alleviation still remain elusive. Intensive efforts have been made to investigate gibberellin and abscisic acid metabolism in seeds, which greatly contributed to the current understanding of seed dormancy mechanisms. Other mechanisms, which might be independent of hormones, or specific to the seed dormancy pathway, are also emerging from genetic analysis of seed dormancy mutants. These studies suggest that chromatin remodeling through histone ubiquitination, methylation and acetylation, which could lead to transcription elongation or gene silencing, may play a significant role in seed dormancy regulation. Small interfering RNA and/or long non-coding RNA might be a trigger of epigenetic changes at the seed dormancy or germination loci, such as DELAY OF GERMINATION1. While new mechanisms are emerging from genetic studies of seed dormancy, novel hypotheses are also generated from seed germination study with high throughput gene expression analysis. Recent studies on tissue-specific gene expression in tomato and Arabidopsis seeds, which suggested possible mechanosensing in the regulatory mechanisms, advanced our understanding of embryo-endosperm interaction and have potential to re-draw the traditional hypotheses or integrate them into a comprehensive scheme. The progress in basic seed science will enable knowledge translation, another frontier of research to be expanded for food and fuel production.

  14. Comparison of two culture media for breaking seed dormancy and ...

    African Journals Online (AJOL)

    ... the percentage germination and days to germination in each of the four species were higher and faster in water with agar medium in comparison to MS growth medium. These results suggest that the Linum seeds have exogenous and endogenous dormancy. Key words: Dormancy, germination, MS media, Linum species, ...

  15. NATURAL ACID IN OVERCOMING PINHA SEED DORMANCY (ANNONA SQUAMOSA L.

    Directory of Open Access Journals (Sweden)

    A. R. Santos

    2018-02-01

    Full Text Available The production of good quality seedlings becomes essential strategy for those who wish to become production that is more competitive. To induce dormancy breaking and germination and emergence of these, the imbibing of natural acid in seeds can be an alternative for the optimization of this process. The aim of this study is to evaluate the dormancy breaking in Anonna seeds squamosa immersed in different natural acid in times through the lemon juice Rangpur (Citrus limonia Osbeck. This work is being conducted in Biotecnogia laboratory greenhouse at the Federal Institute Goiano campus Urutaí where the seeds were soaked in lemon juice Rangpur (C. limonia in five different times, each time constituting a treatment: seeds without soaking in lemon groove variety Cravo '(T1; soaked for 8 hours (T2; soaked for 16 hours (T3; soaked for 24 hours (T4; soaked for 32 hours (T5. The seeds were sown in plastic boxes with dimensions 40 x 27 x 10 cm, containing washed sand substrate, 2 cm deep in spacing of 2 x 2 cm. The germination percentage data were determined up to 45 days after sowing (DAS, and survival to 73 (DAS. After 73 DAS were evaluated after 73 days of sowing, they were evaluated; germination and survival; emergence speed index (EVI; total length of seedlings; shoot length of seedlings and radicle length (cm; Stem diameter (mm; pair of leaf number (MPN; total fresh mass changes (MFT; dry matter of shoot and radicle (g. There was not statistical diseases among treatments. T4 treatment in comparison to others on the numerical difference CTM, NPF, DC and CPA.

  16. Iron Deficiency Prolongs Seed Dormancy in Arabidopsis Plants

    Directory of Open Access Journals (Sweden)

    Irene Murgia

    2017-12-01

    Full Text Available The understanding of seed dormancy, germination and longevity are important goals in plant biology, with relevant applications for agriculture, food industry and also human nutrition. Reactive Oxygen Species (ROS are key molecules involved in the release of dormancy, when their concentrations fall within the so called ‘oxidative window.’ The mechanisms of ROS distribution and sensing in seeds, from dormant to germinating ones, still need elucidation. Also, the impact of iron (Fe deficiency on seed dormancy is still unexplored; this is surprising, given the known pro-oxidant role of Fe when in a free form. We provide evidence of a link between plant Fe nutrition and dormancy of progeny seeds by using different Arabidopsis ecotypes and mutants with different dormancy strengths grown in control soil or under severe Fe deficiency. The latter condition extends the dormancy in several genotypes. The focus on the mechanisms involved in the Fe deficiency-dependent alteration of dormancy and longevity promises to be a key issue in seed (redox biology.

  17. Cancer dormancy and criticality from a game theory perspective.

    Science.gov (United States)

    Wu, Amy; Liao, David; Kirilin, Vlamimir; Lin, Ke-Chih; Torga, Gonzalo; Qu, Junle; Liu, Liyu; Sturm, James C; Pienta, Kenneth; Austin, Robert

    2018-01-01

    The physics of cancer dormancy, the time between initial cancer treatment and re-emergence after a protracted period, is a puzzle. Cancer cells interact with host cells via complex, non-linear population dynamics, which can lead to very non-intuitive but perhaps deterministic and understandable progression dynamics of cancer and dormancy. We explore here the dynamics of host-cancer cell populations in the presence of (1) payoffs gradients and (2) perturbations due to cell migration. We determine to what extent the time-dependence of the populations can be quantitively understood in spite of the underlying complexity of the individual agents and model the phenomena of dormancy.

  18. Induction of 9-cis-epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy.

    Science.gov (United States)

    Martínez-Andújar, Cristina; Ordiz, M Isabel; Huang, Zhonglian; Nonogaki, Mariko; Beachy, Roger N; Nonogaki, Hiroyuki

    2011-10-11

    Full understanding of mechanisms that control seed dormancy and germination remains elusive. Whereas it has been proposed that translational control plays a predominant role in germination, other studies suggest the importance of specific gene expression patterns in imbibed seeds. Transgenic plants were developed to permit conditional expression of a gene encoding 9-cis-epoxycarotenoid dioxygenase 6 (NCED6), a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, using the ecdysone receptor-based plant gene switch system and the ligand methoxyfenozide. Induction of NCED6 during imbibition increased ABA levels more than 20-fold and was sufficient to prevent seed germination. Germination suppression was prevented by fluridone, an inhibitor of ABA biosynthesis. In another study, induction of the NCED6 gene in transgenic seeds of nondormant mutants tt3 and tt4 reestablished seed dormancy. Furthermore, inducing expression of NCED6 during seed development suppressed vivipary, precocious germination of developing seeds. These results indicate that expression of a hormone metabolism gene in seeds can be a sole determinant of dormancy. This study opens the possibility of developing a robust technology to suppress or promote seed germination through engineering pathways of hormone metabolism.

  19. What prolongs a butterfly's life?: Trade-offs between dormancy, fecundity and body size.

    Directory of Open Access Journals (Sweden)

    Elena Haeler

    Full Text Available In butterflies, life span often increases only at the expense of fecundity. Prolonged life span, on the other hand, provides more opportunities for oviposition. Here, we studied the association between life span and summer dormancy in two closely related species of Palearctic Meadow Brown butterflies, the endemic Maniola nurag and the widespread M. jurtina, from two climatic provenances, a Mediterranean and a Central European site, and tested the relationships between longevity, body size and fecundity. We experimentally induced summer dormancy and hence prolonged the butterflies' life in order to study the effects of such a prolonged life. We were able to modulate longevity only in Mediterranean females by rearing them under summer photoperiodic conditions (light 16 h : dark 8 h, thereby more than doubling their natural life span, to up to 246 days. Central European individuals kept their natural average live span under all treatments, as did Mediterranean individuals under autumn treatment (light 11: dark 13. Body size only had a significant effect in the smaller species, M. nurag, where it affected the duration of dormancy and lifetime fecundity. In the larger species, M. jurtina, a prolonged adult life span did, surprisingly, not convey any fecundity loss. In M. nurag, which generally deposited fewer eggs, extended life had a fecundity cost. We conclude that Mediterranen M. jurtina butterflies have an extraordinary plasticity in aging which allows them to extend life span in response to adverse environmental conditions and relieve the time limitation on egg-laying while maintaining egg production at equal levels.

  20. Transcriptional mechanisms associated with seed dormancy and dormancy loss in the gibberellin-insensitive sly1-2 mutant of Arabidopsis thaliana

    Science.gov (United States)

    While widespread transcriptome changes have been previously observed with seed dormancy loss, this study specifically characterized transcriptional changes associated with the increased seed dormancy and dormancy loss of the gibberellin (GA) hormone-insensitive sleepy1-2 (sly1-2) mutant. The SLY1 g...

  1. Association studies of dormancy and cooking quality traits in direct ...

    Indian Academy of Sciences (India)

    Genome-wide scanning, detected a total of seven significant marker-trait associations. (P < 0.01) ... Assam rice; α-amylase; dormancy; cooking quality; association mapping. ...... resource management, association mapping and crop breed- ing.

  2. Water Recovery System Architecture and Operational Concepts to Accommodate Dormancy

    Science.gov (United States)

    Carter, Layne; Tabb, David; Anderson, Molly

    2017-01-01

    Future manned missions beyond low Earth orbit will include intermittent periods of extended dormancy. The mission requirement includes the capability for life support systems to support crew activity, followed by a dormant period of up to one year, and subsequently for the life support systems to come back online for additional crewed missions. NASA personnel are evaluating the architecture and operational concepts that will allow the Water Recovery System (WRS) to support such a mission. Dormancy could be a critical issue due to concerns with microbial growth or chemical degradation that might prevent water systems from operating properly when the crewed mission began. As such, it is critical that the water systems be designed to accommodate this dormant period. This paper identifies dormancy issues, concepts for updating the WRS architecture and operational concepts that will enable the WRS to support the dormancy requirement.

  3. Eukaryotic cell encystation and cancer cell dormancy: is a greater devil veiled in the details of a lesser evil?

    Science.gov (United States)

    Baig, Abdul Mannan; Khan, Naveed Ahmed; Abbas, Farhat

    2015-03-01

    Cancer cell dormancy is the main cause of cancer recurrence and failure of therapy as dormant cells evade not only the anticancer drugs but also the host immune system. These dormant cells veil themselves from detection by imaging and/or using biomarkers, which imposes an additional problem in targeting such cells. A similar form of hibernation process known as encystation is studied in detail for pathogenic unicellular eukaryotic microorganisms. By examination using microarray gene expression profiles, immunocytochemistry tools, and siRNAs during the process of encystation, understanding the covert features of cancer cell dormancy as proposed could be possible. This knowledge can be extended to dormant cancer cells to uncover the mechanisms that underlie this ghost, yet dangerous state of human cancers. We propose a strategy to induce dormancy and exit this state by application of knowledge gained from the encystation induction and retrieval processes in pathogenic eukaryotic microorganisms. Given that early detection and characterization of dormant malignant tumor cells is important as a general strategy to monitor and prevent the development of overt metastatic disease, this homology may enable the design of therapies that could either awake the dormant cell from dormancy to make it available for therapies or prolong such a phase to make cancer appear as a chronic disease.

  4. Effects of elevated CO[sub 2] on time of flowering in four short-day and four long-day species

    Energy Technology Data Exchange (ETDEWEB)

    Reekie, J.Y.C.; Hicklenton, P.R. (Agriculture Canada Research Station, Kentiville, NS (Canada)); Reekie, E.G. (Acadia Univ., Wolfville, NS (Canada))

    1994-01-01

    A study was undertaken to determine if the effect of elevated CO[sub 2] on flowering phenology is a function of the photoperiodic response of the species involved. Four long-day plants, Achillea millefolium, Callistephus chinensis, Campanula isophylla, and Trachelium caeruleum, and four short-day plants, Dendranthema grandiflora, Kalanchoe blossfeldiana, Pharbitis nil, and Xanthium pensylvanicum, were grown under inductive photoperiods (9 h for short day and 17 h for long day) at either 350 or 1000 [mu]l/l CO[sub 2]. Time of visible flower bud formation, flower opening, and final plant biomass were assessed. Elevated CO[sub 2] advanced flower opening in all four long-day species and delayed flowering in all four short-day species. In the long-day species, the effect of CO[sub 2] was primarily on bud initiation; all four species formed buds earlier at high CO[sub 2]. Bud development, the difference in time between flower opening and bud initiation, was advanced in only one long-day species, Callistephus chinensis. Mixed results were obtained for the short-day species. Elevated CO[sub 2] exerted no effects on bud initiation but delayed bud development in Dendranthema and Kalanchoe. In Xanthium, bud initiation rather than bud development was delayed. Data on bud initiation and development were not obtained for Pharbitis. The negative effect of CO[sub 2] upon phenology in the short-day species was not associated with negative effects on growth. Elevated CO[sub 2] increased plant size in both long-day and short-day species. 26 refs., 4 tabs.

  5. Murine hematopoietic stem cell dormancy controlled by induction of a novel short form of PSF1 by histone deacetylase inhibitors

    International Nuclear Information System (INIS)

    Han, Yinglu; Gong, Zhi-Yuan; Takakura, Nobuyuki

    2015-01-01

    Hematopoietic stem cells (HSCs) can survive long-term in a state of dormancy. Little is known about how histone deacetylase inhibitors (HDACi) affect HSC kinetics. Here, we use trichostatin A (TSA), a histone deacetylase inhibitor, to enforce histone acetylation and show that this suppresses cell cycle entry by dormant HSCs. Previously, we found that haploinsufficiency of PSF1, a DNA replication factor, led to attenuation of the bone marrow (BM) HSC pool size and lack of acute proliferation after 5-FU ablation. Because PSF1 protein is present in CD34 + transiently amplifying HSCs but not in CD34 − long-term reconstituting-HSCs which are resting in a dormant state, we analyzed the relationship between dormancy and PSF1 expression, and how a histone deacetylase inhibitor affects this. We found that CD34 + HSCs produce long functional PSF1 (PSF1a) but CD34 − HSCs produce a shorter possibly non-functional PSF1 (PSF1b, c, dominantly PSF1c). Using PSF1a-overexpressing NIH-3T3 cells in which the endogenous PSF1 promoter is suppressed, we found that TSA treatment promotes production of the shorter form of PSF1 possibly by inducing recruitment of E2F family factors upstream of the PSF1 transcription start site. Our data document one mechanism by which histone deacetylase inhibitors affect the dormancy of HSCs by regulating the DNA replication factor PSF1. - Highlights: • Hematopoetic stem cell dormancy is controlled by histone deacetylation inhibitors. • Dormancy of HSCs is associated with a shorter form of non-functional PSF1. • Histone deacetylase inhibitors suppress PSF1 promoter activity

  6. Murine hematopoietic stem cell dormancy controlled by induction of a novel short form of PSF1 by histone deacetylase inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Han, Yinglu; Gong, Zhi-Yuan [Department of Signal Transduction, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Takakura, Nobuyuki, E-mail: ntakaku@biken.osaka-u.ac.jp [Department of Signal Transduction, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Japan Science Technology Agency, CREST, K' s Gobancho, 7, Gobancho, Chiyoda-ku, Tokyo 102-0076 (Japan)

    2015-06-10

    Hematopoietic stem cells (HSCs) can survive long-term in a state of dormancy. Little is known about how histone deacetylase inhibitors (HDACi) affect HSC kinetics. Here, we use trichostatin A (TSA), a histone deacetylase inhibitor, to enforce histone acetylation and show that this suppresses cell cycle entry by dormant HSCs. Previously, we found that haploinsufficiency of PSF1, a DNA replication factor, led to attenuation of the bone marrow (BM) HSC pool size and lack of acute proliferation after 5-FU ablation. Because PSF1 protein is present in CD34{sup +} transiently amplifying HSCs but not in CD34{sup −} long-term reconstituting-HSCs which are resting in a dormant state, we analyzed the relationship between dormancy and PSF1 expression, and how a histone deacetylase inhibitor affects this. We found that CD34{sup +} HSCs produce long functional PSF1 (PSF1a) but CD34{sup −} HSCs produce a shorter possibly non-functional PSF1 (PSF1b, c, dominantly PSF1c). Using PSF1a-overexpressing NIH-3T3 cells in which the endogenous PSF1 promoter is suppressed, we found that TSA treatment promotes production of the shorter form of PSF1 possibly by inducing recruitment of E2F family factors upstream of the PSF1 transcription start site. Our data document one mechanism by which histone deacetylase inhibitors affect the dormancy of HSCs by regulating the DNA replication factor PSF1. - Highlights: • Hematopoetic stem cell dormancy is controlled by histone deacetylation inhibitors. • Dormancy of HSCs is associated with a shorter form of non-functional PSF1. • Histone deacetylase inhibitors suppress PSF1 promoter activity.

  7. Expression Analysis of the MdCIbHLH1 Gene in Apple Flower Buds and Seeds in the Process of Dormancy

    Directory of Open Access Journals (Sweden)

    Yiran Ren

    2016-03-01

    Full Text Available A bHLH transcription factor that is induced by low temperature was found in apple (Malus × domestica Borkh.. To understand the sequence characteristics of the gene, bioinformatics analysis was performed. Furthermore, gene expression patterns of the laminated apple seeds and lateral flower buds were analyzed during the period of dormancy release with semi-quantitative RT-PCR. Based on secondary structure predictions, the results showed that the MdCIbHLH1 protein structure mainly included α-helix and random coil, while β-sheet and extended strand content was less. Semi-quantitative RT-PCR analysis showed that the expression patterns of MdCIbHLH1 were similar in laminated apple seeds and lateral flower buds during the period of dormancy release. Before dormancy release, expression levels of MdCIbHLH1 were high and gradually decreased during the period of dormancy release. These results indicated that MdCIbHLH1 might play an important role during dormancy release in apple seeds and apple buds.

  8. Profiling the Proteome of Mycobacterium tuberculosis during Dormancy and Reactivation*

    Science.gov (United States)

    Gopinath, Vipin; Raghunandanan, Sajith; Gomez, Roshna Lawrence; Jose, Leny; Surendran, Arun; Ramachandran, Ranjit; Pushparajan, Akhil Raj; Mundayoor, Sathish; Jaleel, Abdul; Kumar, Ramakrishnan Ajay

    2015-01-01

    Tuberculosis, caused by Mycobacterium tuberculosis, still remains a major global health problem. The main obstacle in eradicating this disease is the ability of this pathogen to remain dormant in macrophages, and then reactivate later under immuno-compromised conditions. The physiology of hypoxic nonreplicating M. tuberculosis is well-studied using many in vitro dormancy models. However, the physiological changes that take place during the shift from dormancy to aerobic growth (reactivation) have rarely been subjected to a detailed investigation. In this study, we developed an in vitro reactivation system by re-aerating the virulent laboratory strain of M. tuberculosis that was made dormant employing Wayne's dormancy model, and compared the proteome profiles of dormant and reactivated bacteria using label-free one-dimensional LC/MS/MS analysis. The proteome of dormant bacteria was analyzed at nonreplicating persistent stage 1 (NRP1) and stage 2 (NRP2), whereas that of reactivated bacteria was analyzed at 6 and 24 h post re-aeration. Proteome of normoxially grown bacteria served as the reference. In total, 1871 proteins comprising 47% of the M. tuberculosis proteome were identified, and many of them were observed to be expressed differentially or uniquely during dormancy and reactivation. The number of proteins detected at different stages of dormancy (764 at NRP1, 691 at NRP2) and reactivation (768 at R6 and 983 at R24) was very low compared with that of the control (1663). The number of unique proteins identified during normoxia, NRP1, NRP2, R6, and R24 were 597, 66, 56, 73, and 94, respectively. We analyzed various biological functions during these conditions. Fluctuation in the relative quantities of proteins involved in energy metabolism during dormancy and reactivation was the most significant observation we made in this study. Proteins that are up-regulated or uniquely expressed during reactivation from dormancy offer to be attractive targets for therapeutic

  9. Mixed-mode oscillations and chaos in a prey-predator system with dormancy of predators.

    Science.gov (United States)

    Kuwamura, Masataka; Chiba, Hayato

    2009-12-01

    It is shown that the dormancy of predators induces mixed-mode oscillations and chaos in the population dynamics of a prey-predator system under certain conditions. The mixed-mode oscillations and chaos are shown to bifurcate from a coexisting equilibrium by means of the theory of fast-slow systems. These results may help to find experimental conditions under which one can demonstrate chaotic population dynamics in a simple phytoplankton-zooplankton (-resting eggs) community in a microcosm with a short duration.

  10. Dormancy contributes to the maintenance of microbial diversity.

    Science.gov (United States)

    Jones, Stuart E; Lennon, Jay T

    2010-03-30

    Dormancy is a bet-hedging strategy used by a variety of organisms to overcome unfavorable environmental conditions. By entering a reversible state of low metabolic activity, dormant individuals become members of a seed bank, which can determine community dynamics in future generations. Although microbiologists have documented dormancy in both clinical and natural settings, the importance of seed banks for the diversity and functioning of microbial communities remains untested. Here, we develop a theoretical model demonstrating that microbial communities are structured by environmental cues that trigger dormancy. A molecular survey of lake ecosystems revealed that dormancy plays a more important role in shaping bacterial communities than eukaryotic microbial communities. The proportion of dormant bacteria was relatively low in productive ecosystems but accounted for up to 40% of taxon richness in nutrient-poor systems. Our simulations and empirical data suggest that regional environmental cues and dormancy synchronize the composition of active communities across the landscape while decoupling active microbes from the total community at local scales. Furthermore, we observed that rare bacterial taxa were disproportionately active relative to common bacterial taxa, suggesting that microbial rank-abundance curves are more dynamic than previously considered. We propose that repeated transitions to and from the seed bank may help maintain the high levels of microbial biodiversity that are observed in nearly all ecosystems.

  11. Mechanisms of Cancer Cell Dormancy--Another Hallmark of Cancer?

    Science.gov (United States)

    Yeh, Albert C; Ramaswamy, Sridhar

    2015-12-01

    Disease relapse in cancer patients many years after clinical remission, often referred to as cancer dormancy, is well documented but remains an incompletely understood phenomenon on the biologic level. Recent reviews have summarized potential models that can explain this phenomenon, including angiogenic, immunologic, and cellular dormancy. We focus on mechanisms of cellular dormancy as newer biologic insights have enabled better understanding of this process. We provide a historical context, synthesize current advances in the field, and propose a mechanistic framework that treats cancer cell dormancy as a dynamic cell state conferring a fitness advantage to an evolving malignancy under stress. Cellular dormancy appears to be an active process that can be toggled through a variety of signaling mechanisms that ultimately downregulate the RAS/MAPK and PI(3)K/AKT pathways, an ability that is preserved even in cancers that constitutively depend on these pathways for their growth and survival. Just as unbridled proliferation is a key hallmark of cancer, the ability of cancer cells to become quiescent may be critical to evolving malignancies, with implications for understanding cancer initiation, progression, and treatment resistance. ©2015 American Association for Cancer Research.

  12. Mechanisms of Cancer Cell Dormancy – Another Hallmark of Cancer?

    Science.gov (United States)

    Yeh, Albert C.; Ramaswamy, Sridhar

    2015-01-01

    Disease relapse in cancer patients many years after clinical remission, often referred to as cancer dormancy, is well documented but remains an incompletely understood phenomenon on the biological level. Recent reviews have summarized potential models that can explain this phenomenon, including angiogenic, immunologic, and cellular dormancy. We focus on mechanisms of cellular dormancy as newer biological insights have enabled better understanding of this process. We provide a historical context, synthesize current advances in the field, and propose a mechanistic framework that treats cancer cell dormancy as a dynamic cell state conferring a fitness advantage to an evolving malignancy under stress. Cellular dormancy appears to be an active process that can be toggled through a variety of signaling mechanisms that ultimately down-regulate the Ras/MAPK and PI(3)K/AKT pathways, an ability that is preserved even in cancers that constitutively depend on these pathways for their growth and survival. Just as unbridled proliferation is a key hallmark of cancer, the ability of cancer cells to become quiescent may be critical to evolving malignancies, with implications for understanding cancer initiation, progression, and treatment resistance. PMID:26354021

  13. The involvement of mitochondrial phosphate transporter in accelerating bud dormancy release during chilling treatment of tree peony (Paeonia suffruticosa).

    Science.gov (United States)

    Huang, Xin; Zhu, Wei; Dai, Silan; Gai, Shupeng; Zheng, Guosheng; Zheng, Chengchao

    2008-09-01

    A cDNA clone was isolated from tree peony (Paeonia suffruticosa) subtractive cDNA library of burst buds and characterized with regard to its sequence, expression in response to chilling treatment during the release of bud dormancy, and its function in transgenic Arabidopsis thaliana. The clone, designated as PsMPT, contains 1,615 nucleotides with an open reading frame of 1,119 nucleotides, and the deduced amino acid sequence shows high homology with mitochondrial phosphate transporters (MPTs) from various organisms. The mRNA accumulation of PsMPT in tree peony was strongly induced by chilling treatment during the release of bud dormancy. When the treated plants were transferred to normal growth conditions, the level of PsMPT transcripts induced by sufficient chilling could be maintained high, whereas that induced by insufficient chilling decreased sharply. The transgenic Arabidopsis plants that overexpress PsMPT showed rapid growth and earlier flowering than wild-type plants. ATP contents in the transgenic plants were much higher than that in wild-type plants through various developmental stages. Together, these results suggest that the product of PsMPT is a MPT and might play an important role during the release of bud dormancy in tree peony.

  14. Analysis of natural allelic variation at seed dormancy loci of Arabidopsis thaliana

    NARCIS (Netherlands)

    Alonso-Blanco, C.; Bentsink, L.; Hanhart, C.J.; Vries, de M.H.C.; Koornneef, M.

    2003-01-01

    Arabidopsis accessions differ largely in their seed dormancy behavior. To understand the genetic basis of this intraspecific variation we analyzed two accessions: the laboratory strain Landsberg erecta (Ler) with low dormancy and the strong-dormancy accession Cape Verde Islands (Cvi). We used a

  15. Mechanisms of seed dormancy in an annual population of Zostera marina (eelgrass) from the Netherlands)

    NARCIS (Netherlands)

    Harrison, P.G.

    1991-01-01

    Mechanisms of dormancy of seeds from an annual population of the seagrass Zostera marina L. (eelgrass) in the SW Netherlands were investigated in the laboratory. Both physiological dormancy (a requirement for reduced salinity for germination) and physical dormancy (imposed by the seed coat) existed

  16. Initial characterisation of low and high seed dormancy populations of Lolium rigidum produced by repeated selection.

    Science.gov (United States)

    Goggin, Danica E; Emery, R J Neil; Powles, Stephen B; Steadman, Kathryn J

    2010-10-15

    The physiological and biochemical bases of seed dormancy in Lolium rigidum (annual ryegrass) are largely unknown, and study of this process is complicated by the outcrossing nature of the species and the strong influence of environment on seed dormancy. In order to identify heritable biochemical factors contributing to seed dormancy in L. rigidum, seeds from a field-collected population were used to select sub-populations with consistently low or high seed dormancy over four generations. Low-dormancy seeds showed constitutive alpha-amylase activity prior to imbibition, higher concentrations of polyphenols and cis-zeatin, and lower abscisic acid and cis-zeatin riboside concentrations than high-dormancy seeds. Selection for high dormancy was associated with a reduction in response to dark-stratification for 21d at 20 degrees C (an effective means of releasing dormancy in the original, unselected population) over successive generations, but fluridone remained effective in breaking dormancy. Crossing of low- and high-dormancy populations indicated that dormancy level was not dependent upon the maternal genotype of the seed, and that the constitutive alpha-amylase activity and high seed anthocyanin concentrations characteristic of the low-dormancy populations were not correlated to high basal germination ability. Copyright (c) 2010 Elsevier GmbH. All rights reserved.

  17. Considering Intermittent Dormancy in an Advanced Life Support Systems Architecture

    Science.gov (United States)

    Sargusingh, Miriam J.; Perry, Jay L.

    2017-01-01

    Many advanced human space exploration missions being considered by the National Aeronautics and Space Administration (NASA) include concepts in which in-space systems cycle between inhabited and uninhabited states. Managing the life support system (LSS) may be particularly challenged during these periods of intermittent dormancy. A study to identify LSS management challenges and considerations relating to dormancy is described. The study seeks to define concepts suitable for addressing intermittent dormancy states and to evaluate whether the reference LSS architectures being considered by the Advanced Exploration Systems (AES) Life Support Systems Project (LSSP) are sufficient to support this operational state. The primary focus of the study is the mission concept considered to be the most challenging-a crewed Mars mission with an extensive surface stay. Results from this study are presented and discussed.

  18. HONSU, a protein phosphatase 2C, regulates seed dormancy by inhibiting ABA signaling in Arabidopsis.

    Science.gov (United States)

    Kim, Woohyun; Lee, Yeon; Park, Jeongmoo; Lee, Nayoung; Choi, Giltsu

    2013-04-01

    Seed dormancy, a seed status that prohibits germination even in the presence of inductive germination signals, is a poorly understood process. To identify molecular components that regulate seed dormancy, we screened T-DNA insertion lines and identified a mutant designated honsu (hon). HON loss-of-function mutants display deep seed dormancy, whereas HON-overexpressing lines display shallow seed dormancy. HON encodes a seed-specific group A phosphatase 2C (PP2C) and is one of the major negative regulators of seed dormancy among group A PP2Cs. Like other PP2C family members, HON interacts with PYR1/RCAR11 in the presence of ABA. Our analysis indicates that HON inhibits ABA signaling and activates gibberellic acid signaling, and both of these conditions must be satisfied to promote the release of seed dormancy. However, HON mRNA levels are increased in mutants displaying deep seed dormancy or under conditions that deepen seed dormancy, and decreased in mutants displaying shallow seed dormancy or under conditions that promote the release of seed dormancy. Taken together, our results indicate that the expression of HON mRNA is homeostatically regulated by seed dormancy.

  19. Breaking Dormancy In Gmelina arborea Roxb. Through Treatment ...

    African Journals Online (AJOL)

    Seeds of Gmelina arborea Roxb. were subjected to different treatment [chemical scarification with concentrated sulphuric acid (H2S04), potasium nitrate (KNO3), potasium nitrite (KNO2) and alternating temperature regimes] to ascertain the best treatment for terminating dormancy in the seeds. Initial viability and germination ...

  20. genetics and inheritance of seed dormancy inflicted by seed

    African Journals Online (AJOL)

    Mgina

    ABSTRACT. The study was undertaken to investigate the genetic mode of inheritance of dormancy imposed by the hull (seed coat) in rice seeds. Freshly harvested seeds of parents, F1 and F2 populations of a cross between a dormant cultivar Kisegese and non-dormant strain K2004 were used. Germination test of the ...

  1. Overcoming dormancy and enhancing germination of Sphaeralcea munroana seeds

    Science.gov (United States)

    Olga A. Kildisheva; R. Kasten Dumroese; Anthony S. Davis

    2011-01-01

    The results of a series of experiments involving a variety of dormancy-breaking treatments indicate that Munro's globemallow [Sphaeralcea munroana (Douglas) Spach] seeds are physically dormant, possess a cap-like structure in the occlusion of the water gap, which inhibits imbibition, and can be artificially dislodged through boiling water scarification. The...

  2. Spatially heterogeneous stochasticity and the adaptive diversification of dormancy.

    Science.gov (United States)

    Rajon, E; Venner, S; Menu, F

    2009-10-01

    Diversified bet-hedging, a strategy that leads several individuals with the same genotype to express distinct phenotypes in a given generation, is now well established as a common evolutionary response to environmental stochasticity. Life-history traits defined as diversified bet-hedging (e.g. germination or diapause strategies) display marked differences between populations in spatial proximity. In order to find out whether such differences can be explained by local adaptations to spatially heterogeneous environmental stochasticity, we explored the evolution of bet-hedging dormancy strategies in a metapopulation using a two-patch model with patch differences in stochastic juvenile survival. We found that spatial differences in the level of environmental stochasticity, restricted dispersal, increased fragmentation and intermediate survival during dormancy all favour the adaptive diversification of bet-hedging dormancy strategies. Density dependency also plays a major role in the diversification of dormancy strategies because: (i) it may interact locally with environmental stochasticity and amplify its effects; however, (ii) it can also generate chaotic population dynamics that may impede diversification. Our work proposes new hypotheses to explain the spatial patterns of bet-hedging strategies that we hope will encourage new empirical studies of this topic.

  3. effect of hydrogen peroxide and thiourea on dormancy breaking of ...

    African Journals Online (AJOL)

    ACSS

    the hydrogen peroxide (H2O2) (Claassens and. Vreugdenhil, 2000; Suttle, 2004). Hence, the objective of this study was to evaluate the effects of hydrogen peroxide and thiourea on dormancy and sprouting of potato microtubers and field grown tubers is described. MATERIELS AND METHODS. Production of microtubers.

  4. Carbohydrate metabolism during potato tuber dormancy and sprouting

    NARCIS (Netherlands)

    Claassens, M.M.J.

    2002-01-01

    Potato tuber dormancy is part of the vegetative life cycle of potato. It refers to a period, in which no growth is occurring, although the tuber is stored under conditions that are favourable for growth. Factors in the tuber are responsible for this growth arrest; soon

  5. Ethylene, a key factor in the regulation of seed dormancy

    Directory of Open Access Journals (Sweden)

    Françoise eCORBINEAU

    2014-10-01

    Full Text Available Ethylene is an important component of the gaseous environment, and regulates numerous plant developmental processes including seed germination and seedling establishment. Dormancy, the inability to germinate in apparently favorable conditions, has been demonstrated to be regulated by the hormonal balance between abscisic acid (ABA and gibberellins (GAs. Ethylene plays a key role in dormancy release in numerous species, the effective concentrations allowing the germination of dormant seeds ranging between 0.1 and 200 μL L-1. Studies using inhibitors of ethylene biosynthesis or of ethylene action and analysis of mutant lines altered in genes involved in the ethylene signaling pathway (etr1, ein2, ain1, etr1, and erf1 demonstrate the involvement of ethylene in the regulation of germination and dormancy. Ethylene counteracts ABA effects through a regulation of ABA metabolism and signaling pathways. Moreover, ethylene insensitive mutants in Arabidopsis are more sensitive to ABA and the seeds are more dormant. Numerous data also show an interaction between ABA, GAs and ethylene metabolism and signaling pathways. It has been increasingly demonstrated that reactive oxygen species (ROS may play a significant role in the regulation of seed germination interacting with hormonal signaling pathways. In the present review the responsiveness of seeds to ethylene will be described, and the key role of ethylene in the regulation of seed dormancy via a cross-talk between hormones and other signals will be discussed.

  6. Perspectives of biotechnologies based on dormancy phenomenon for space researches

    Science.gov (United States)

    Alekseev, V.; Sychev, V.; Layus, D.; Levinsky, M.; Novikova, N.; Zakhodnova, T.

    Long term space missions will require a renewable source of food and an efficient method to recycle oxygen Plants especially aquatic micro algae provide an obvious solution to these problems However long duration plant growth and reproduction in space that is necessary for transportation of a control ecological life support system CELSS from Earth to other planets are problematic The introduction of heterotrophs in space CELSS is a more formidable problem as the absence of gravity creates additional difficulties for their life Dormancy phenomenon protected a great many animals and plants in harsh environmental conditions within a special resting phases of life cycle lasting from months up to hundred years This phenomenon can be quite perspective as a tool to overcome difficulties with CELSS transportation in space missions Cryptobiotic stages of microbes fungi unicellular algae and protists can survive in open space conditions that is important for interplanetary quarantine and biological security inside spacecraft Searching for life outside the Earth at such planet like Mars with extremely variable environment should be oriented on dormancy as crucial phases of a life cycle in such organisms Five major research programs aimed on study dormancy phenomenon for exobiology purposes and creation of new biotechnologies are discussed List of species candidate components of CELSS with dormancy in their life cycle used in space experiments at the Russian segment of International Space Station now includes 26 species from bacteria to fish The

  7. Role of protein and mRNA oxidation in seed dormancy and germination

    Directory of Open Access Journals (Sweden)

    hayat eel-maarouf-bouteau

    2013-04-01

    Full Text Available Reactive oxygen species (ROS are key players in the regulation of seed germination and dormancy. Although their regulated accumulation is a prerequisite for germination, the cellular basis of their action remains unknown, but very challenging to elucidate due to the lack of specificity of these compounds that can potentially react with all biomolecules. Among these, nucleic acids and proteins are very prone to oxidative damage. RNA is highly sensitive to oxidation because of its single-stranded structure and the absence of a repair system. Oxidation of mRNAs induces their decay through processing bodies or results in the synthesis of aberrant proteins through altered translation. Depending on the oxidized amino acid, ROS damage of proteins can be irreversible (i.e. carbonylation thus triggering the degradation of the oxidized proteins by the cytosolic 20S proteasome or can be reversed through the action of thioredoxins, peroxiredoxins or glutaredoxins (cysteine oxidation or by methionine sulfoxide reductase (methionine oxidation. Seed dormancy alleviation in the dry state, referred to as after-ripening, requires both selective mRNA oxidation and protein carbonylation. Similarly, seed imbibition of non-dormant seeds is associated with targeted oxidation of a subset of proteins. Altogether, these specific features testify that such oxidative modifications play important role in commitment of the cellular functioning toward germination completion.

  8. [Reason for dormancy of Cuscuta chinensis seed and solving method].

    Science.gov (United States)

    Wang, Xuemin; He, Jiaqing; Cai, Jing; Dong, Zhenguo

    2010-02-01

    To study the reason for the deep dormancy of the aged Cuscuta chinensis seed and find the solving method. The separated and combined treatments were applied in the orthogonal designed experiments. The aged seed had well water-absorbency; the water and ethanol extracts of the seeds showed an inhibition effect on germination capacity of the seeds. The main reason for the deep dormancy of aged C. chinensis seed is the inhibitors existed in seed. There are two methods to solve the problem. The seeds is immersed in 98% of H2SO4 for 2 min followed by 500 mg x L(-1) of GA3 treatment for 60 min, or in 100 mg x L(-1) of NaOH for 20 min followed by 500 mg x L(-1) of GA3 treatment for 120 min.

  9. Dormancy break in Pithecellobium dulce (Roxb. Benth. seeds

    Directory of Open Access Journals (Sweden)

    Francisco Elder Carlos Bezerra Pereira

    2015-02-01

    Full Text Available This research aimed to evaluate different methods for breaking dormancy in seeds of Pithecellobium dulce (Roxb. Benth., arboreal species of multiple use in the semiarid region of Northeast Brazil. The treatments were: control – intact seeds (T1; immersion in water until it reaches 80 °C (T2, and 100 °C (T3, concentrated sulfuric acid for five minutes (T4, 10 minutes (T5 , and 15 minutes (T6, mechanical scarification with sandpaper number 80 (T7, mechanical scarification with sandpaper number 80 + immersion in water for six hours (T8, and for 12 hours (T9, soaking in water for 24 hours (T10, and for 48 hours (T11. The characteristics evaluated were such: emergency, mean emergency time, shoot length, root length, number of leaves, leaf area and total dry matter. The best method for breaking dormancy of seeds of Pithecellobium dulce (Roxb. Benth. is mechanical scarification with sandpaper number 80.

  10. Ultrasonic actuation for MEMS dormancy-related stiction reduction

    Science.gov (United States)

    Kaajakari, Ville; Kan, Shyi-Herng; Lin, Li-Jen; Lal, Amit; Rodgers, M. Steven

    2000-08-01

    The use of ultrasonic pulses incident on surface micromachines has been shown to reduce dormancy-related failure. We applied ultrasonic pulses from the backside of a silicon substrate carrying SUMMiT processed surface micromachined rotors, used earlier as ultrasonic motors. The amplitude of the pulses was less than what is required to actuate the rotor (sub-threshold actuation). By controlling the ultrasonic pulse exposure time it was found that pulsed samples had smaller actuation voltages as compared to non-pulsed samples after twelve-hour dormancy. This result indicates that the micromachine stiction to surfaces during dormant period can be effectively eliminated, resulting in long-term stability of surface micromachines in critical applications.

  11. Live virus-free or die: coupling of antivirus immunity and programmed suicide or dormancy in prokaryotes

    Directory of Open Access Journals (Sweden)

    Makarova Kira S

    2012-11-01

    Full Text Available Abstract Background The virus-host arms race is a major theater for evolutionary innovation. Archaea and bacteria have evolved diverse, elaborate antivirus defense systems that function on two general principles: i immune systems that discriminate self DNA from nonself DNA and specifically destroy the foreign, in particular viral, genomes, whereas the host genome is protected, or ii programmed cell suicide or dormancy induced by infection. Presentation of the hypothesis Almost all genomic loci encoding immunity systems such as CRISPR-Cas, restriction-modification and DNA phosphorothioation also encompass suicide genes, in particular those encoding known and predicted toxin nucleases, which do not appear to be directly involved in immunity. In contrast, the immunity systems do not appear to encode antitoxins found in typical toxin-antitoxin systems. This raises the possibility that components of the immunity system themselves act as reversible inhibitors of the associated toxin proteins or domains as has been demonstrated for the Escherichia coli anticodon nuclease PrrC that interacts with the PrrI restriction-modification system. We hypothesize that coupling of diverse immunity and suicide/dormancy systems in prokaryotes evolved under selective pressure to provide robustness to the antivirus response. We further propose that the involvement of suicide/dormancy systems in the coupled antivirus response could take two distinct forms: 1 induction of a dormancy-like state in the infected cell to ‘buy time’ for activation of adaptive immunity; 2 suicide or dormancy as the final recourse to prevent viral spread triggered by the failure of immunity. Testing the hypothesis This hypothesis entails many experimentally testable predictions. Specifically, we predict that Cas2 protein present in all cas operons is a mRNA-cleaving nuclease (interferase that might be activated at an early stage of virus infection to enable incorporation of virus

  12. Reproductive dormancy in boll-weevil from populations of the midwest of Brazil.

    Science.gov (United States)

    Paula, D P; Claudino, D; Timbó, R V; Miranda, J E; Bemquerer, M P; Ribeiro, A C J; Sujii, E R; Fontes, E M G; Pires, C S S

    2013-02-01

    The boll weevil (Anthonomus grandis Boheman) (Coleoptera: Curculionidae) is an introduced pest in Brazil, which in 30 yr has successfully expanded to various eco-regions and became the most important pest of cotton (Gossypium hirsutum, Malvaceae). Given the limited knowledge about the adaptive mechanisms that allowed successful establishment of the pest population in a tropical region, in this work we studied the potential of the Midwest population of boll weevils to enter a reproductive dormancy and identified the importance of the feeding source for induction of dormancy. We investigated morphological and physiological characters as indicators of the dormancy. We also investigated the occurrence of reproductive dormancy in boll weevils populations from cotton farms of the Midwestern region of Brazil during the cotton and noncotton seasons of 2009 and 2010. The studies revealed that boll weevils entered facultative reproductive dormancy; however, unlike what has been observed for boll weevils from temperate and subtropical regions, the hypertrophy of fat body and hexamerin levels did not straightly correlated to reproductive dormancy. The food source and field conditions during early adult development were decisive factor for the induction of reproductive dormancy. The incidence of reproductive dormancy increased progressively as the phenology of cotton plant advanced, reaching approximately 90% at the end of the crop season. During the noncotton season, the boll weevil was predominantly found in reproductive dormancy, especially females; however, there is evidence of use of multiple adaptive strategies to colonize the next harvest.

  13. Maturation, temperature and breaking dormancy of Comanthera seeds

    OpenAIRE

    Andréa Santos Oliveira; Maria Laene Moreira Carvalho; Cláudio das Neves Vieira Bárbara; Tanismare Tatiana Almeida; Marcela Carlota Nery

    2016-01-01

    Given the importance of “everlasting” plants for their ornamental value and vulnerability to extractive practices, studies to ensure the propagation of the species are indispensable. The aim of this study was to assess whether there is an association between seed coat color and the quality of everlasting seeds, in the presence or absence of dormancy. Four species (Comanthera elegans, C. nitida, C. bisculata, and Comanthera sp.) were separated with respect to seed coat color and underwent germ...

  14. Seasonal pattern of seed dormancy in parthenium hysterophorus L

    International Nuclear Information System (INIS)

    Arshad Javaid, A.; Shafique, S.; Shafique, S.

    2010-01-01

    Earlier non-conclusive results have been reported on the initial dormancy status of parthenium (Parthenium hysterophorus L.) seeds. The present study reports the seasonal dormancy pattern of parthenium in Lahore, Pakistan where there are four distinct seasons viz. summer, autumn, winter and spring in a year. Mature parthenium seeds were collected on the last day of each month from January to December 2006 and investigations for their germination percentage and rate of germination were started on the next day. Parthenium seeds collected during coldest months of January and December showed highest germination of 100% with germination rate of 33.3% per day. Conversely, seeds collected in summer months of April to September exhibited lowest germination of 0-7% and germination rate of 0-1.75% per day. Seeds collected in rest of the months showed variable final germination percentage and germination rate ranging from 30-97% and 3.8-17.4%, respectively. Both the final germination and germination rate showed a highly significant negative correlation with the solar radiation and environmental temperature during the seed development period. The present study concludes that dormancy in parthenium seeds depends upon the temperature and solar radiation during the seed development period. (author)

  15. Methods for overcoming dormancy in Stryphnodendron pulcherrimum seeds

    Directory of Open Access Journals (Sweden)

    Adriano Gonçalves Pereira

    2016-09-01

    Full Text Available Seed dormancy is a phenomenon observed in several tropical species. This condition causes low and non-uniform germination. The present study was designed to identify an efficient method of breaking seed dormancy in Stryphnodendron pulcherrimum. Seeds of four mother plants were subjected to the following treatments: immersion in sulfuric acid for 2, 4, 6, 8, 10 and 12 min and scarification on 150-grit sandpaper. Seeds were sown on substrate containing sand and sawdust (1:1. It was evaluate the days to onset seedlings emergence, seedlings emergence (SE, emergence speed index (ESI, germination (G, hard seeds (HS, dead seeds (DS, dormant seeds (DMS, abnormal seedlings (AS and dry mass of aerial part (DMAP and roots (DMR. The experimental design was completely randomized with four replications of 25 seeds for each treatment. Data were subjected to analysis of variance and means compared by Tukey’s test (p < 0.05. Significant differences among treatments were observed for ESI, SE, G, HS, DMAP and DMR. Highest HS was observed in control treatment (85%. Highest G was observed in seeds scarified with sulfuric acid for 10 min (82% and 12 min (74%. These treatments also showed highest ESI, DMAP and DMR, indicating that these scarification treatments were the most efficient in overcoming dormancy.

  16. Hormonal Regulation of Dormancy in Developing Sorghum Seeds.

    Science.gov (United States)

    Steinbach, H. S.; Benech-Arnold, R. L.; Sanchez, R. A.

    1997-01-01

    The role of abscisic acid (ABA) and gibberellic acid (GA) in determining the dormancy level of developing sorghum (Sorghum bicolor [L.] Moench.) seeds from varieties presenting contrasting preharvest sprouting behavior (Redland B2, susceptible; IS 9530, resistant) was investigated. Panicles from both varieties were sprayed soon after pollination with fluridone or paclobutrazol to inhibit ABA and GA synthesis, respectively. Fluridone application to the panicles increased germinability of Redland B2 immature caryopses, whereas early treatment with paclobutrazol completely inhibited germination of this variety during most of the developmental period. Incubating caryopses in the presence of 100 [mu]M GA4+7 overcame the inhibitory effect of paclobutrazol, but also stimulated germination of seeds from other treatments. IS 9530 caryopses presented germination indices close to zero until physiological maturity (44 d after pollination) in control and paclobutrazol-treated particles. However, fluridone-treated caryopses were released from dormancy earlier than control and paclobutrazol-treated caryopses. Incubation in the presence of GA4+7 stimulated germination of caryopses from all treatments. Our results support the proposition that a low dormancy level (which is related to a high preharvest sprouting susceptibility) is determined not only by a low embryonic sensitivity to ABA, but also by a high GA content or sensitivity.

  17. PpHB22, a member of HD-Zip proteins, activates PpDAM1 to regulate bud dormancy transition in 'Suli' pear (Pyrus pyrifolia White Pear Group).

    Science.gov (United States)

    Yang, Qinsong; Niu, Qingfeng; Li, Jianzhao; Zheng, Xiaoyan; Ma, Yunjing; Bai, Songling; Teng, Yuanwen

    2018-06-01

    Homeodomain-leucine zipper (HD-Zip) proteins, which form one of the largest and most diverse families, regulate many biological processes in plants, including differentiation, flowering, vascular development, and stress signaling. Abscisic acid (ABA) has been proved to be one of the key regulators of bud dormancy and to influence several HD-Zip genes expression. However, the role of HD-Zip genes in regulating bud dormancy remains unclear. We identified 47 pear (P. pyrifolia White Pear Group) HD-Zip genes, which were classified into four subfamilies (HD-Zip I-IV). We further revealed that gene expression levels of some HD-Zip members were closely related to ABA concentrations in flower buds during dormancy transition. Exogenous ABA treatment confirmed that PpHB22 and several other HD-Zip genes responded to ABA. Yeast one-hybrid and dual luciferase assay results combining subcellular localization showed that PpHB22 was present in nucleus and directly induced PpDAM1 (dormancy associated MADS-box 1) expression. Thus, PpHB22 is a negative regulator of plant growth associated with the ABA response pathway and functions upstream of PpDAM1. These findings enrich our understanding of the function of HD-Zip genes related to the bud dormancy transition. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  18. Dim light at night interferes with the development of the short-day phenotype and impairs cell-mediated immunity in Siberian hamsters (Phodopus sungorus).

    Science.gov (United States)

    Aubrecht, Taryn G; Weil, Zachary M; Nelson, Randy J

    2014-10-01

    Winter is a challenging time to survive and breed outside of the tropics. Animals use day length (photoperiod) to regulate seasonally appropriate adaptations in anticipation of challenging winter conditions. The net result of these photoperiod-mediated adjustments is enhanced immune function and increased survival. Thus, the ability to discriminate day length information is critical for survival and reproduction in small animals. However, during the past century, urban and suburban development has rapidly expanded and filled the night sky with light from various sources, obscuring crucial light-dark signals, which alters physiological interpretation of day lengths. Furthermore, reduced space, increased proximity to people, and the presence of light at night may act as stressors for small animals. Whereas acute stressors typically enhance immune responses, chronic exposure to stressors often impairs immune responses. Therefore, we hypothesized that the combination of dim light at night and chronic stress interferes with enhanced cell-mediated immunity observed during short days. Siberian hamsters (Phodopus sungorus) were assigned to short or long days with dark nights (0 lux) or dim (5 lux) light at night for 10 weeks. Following 2 weeks of chronic restraint (6 hr/day), a model of chronic stress, delayed type hypersensitivity (DTH) responses were assessed. Both dim light at night and restraint reduced the DTH response. Dim light at night during long nights produced an intermediate short day phenotype. These results suggest the constant presence of light at night could negatively affect survival of photoperiodic rodents by disrupting the timing of breeding and immune responses. © 2014 Wiley Periodicals, Inc.

  19. Biochemical mechanism of radiation-induced dormancy in potatoes

    International Nuclear Information System (INIS)

    Nair, P.M.; Ussuf, K.K.; Janave, M.T.; Satyanarayana, V.; Pendharkar, M.B.

    1983-01-01

    The studies described here will show that after gamma irradiation the dormant bud tissue of potato exhibits a transient metabolic activation. During this period of active metabolic state, the tissue is capable of synthesis of DNA, RNA and protein. Apart from this there is increased utilization of carbohydrate for the production of the energy source ATP, to meet the demand for these processes. The site of active protein synthesis during this transient phase of activation has been recognized as nuclei of the bud tissue and the synthesis of new proteins of the nuclei takes place within one to two hours after irradiation. The synthesis of nuclear acidic proteins was increased to about 3 to 5 fold during the activation period compared to unirradiated bud tissue. The increase in acidic protein synthesis lasted for 4.5 hr. During the time there was no synthesis of histones. The synthesis of histones started only 7 hr after irradiation showing about 10 fold increase over the control bud tissue. The increase in the concentration of non-histone protein prior to active RNA synthetic phase (2 hr) is suggestive of their involvement in the metabolic activation ensured after gamma irradiation. Gamma irradiation adversely affected the IAA synthesising system and the production of IAA. Treatment with low concentrations of IAA within 6 hr after irradiation could restore the IAA synthesising capacity as well as reversal of sprout inhibition. (author)

  20. Treatment-Induced Autophagy Associated with Tumor Dormancy and Relapse

    Science.gov (United States)

    2015-07-01

    one hallmark may have an impact on other targets that are relevant, especially if both are linked via signal- ing pathways. Accordingly, the cross...the whole disease as the endpoint (e.g. cancer) may be inappropriate, especially when exposures to individual chemicals can produce relevant (but not...the Junta de Andalucia (PI-0306-2012); Amaya Azqueta would like to thank the Ministerio de Educacion y Ciencia (‘Juande la Cierva’ pro- gramme, 2009

  1. Treatment Induced Autophagy Associated with Tumor Dormancy and Relapse

    Science.gov (United States)

    2016-07-01

    they sleep ? J Pharmacol Exp Ther 2012; 343(3):763-78. 9. Michaud M, Martins I, Sukkurwala AQ, Adjemian S, Ma Y, Pellegatti P, Shen S, Kepp O, Scoazec...EA and Gewirtz D.A. Radiosensitization by PARP Inhibition in DNA Repair Proficient and Deficient Tumor Cells: Proliferative Recovery in Senescent

  2. Treatment-Induced Autophagy Associated with Tumor Dormancy and Relapse

    Science.gov (United States)

    2016-07-01

    which account for a majority of all cancer deaths, is limited. The application of immunother- apy to highly proliferative tumors renders the tumors prone...ELISA kit (BD Biosciences, Franklin Lakes, NJ, USA), according to the manufacturer’s protocol [5]. Characterization of splenocytes and tumor...Horton, H. F., Fouser, L., Carter, L., Ling, V., Bowman, M. R., Carreno, B. M., Collins, M., Wood , C. R., Honjo, T. (2000) Engagement of the PD-1

  3. Treatment-Induced Autophagy Associated with Tumor Dormancy and Relapse

    Science.gov (United States)

    2017-07-01

    Monogr. 10021, 57e71. http://dx.doi.org/10.1093/jncimonographs/lgh014. McWhinney, S.R., Goldberg , R.M., McLeod, H.L., 2009. Platinum neurotoxicity... variations on a common theme of self-eating? Nat Rev Mol Cell Biol 13: 7 – 12 Cohen-Kaplan V, Livneh I, Avni N, Fabre B, Ziv T, Kwon YT, Ciechanover A (2016...Hippo kinases STK3/STK4 is essential for autophagy. Mol Cell 57: 55 – 68 Wing SS, Chiang HL, Goldberg AL, Dice JF (1991) Proteins containing peptide

  4. Dormancy and cold hardiness transitions in wine grape cultivars Chardonnay and Cabernet Sauvignon

    Science.gov (United States)

    Dormancy and cold hardiness influence grapevine (Vitis vinifera L.) susceptibility to cold injury, which is a major cause of economic loss in high latitude growing regions. The objectives of this study were to compare dormancy and cold hardiness transitions in wine grape cultivars considered more (C...

  5. A simulation model for seasonal changes in dormancy and germination of weed seeds

    NARCIS (Netherlands)

    Vleeshouwers, L.M.; Bouwmeester, H.J.

    2001-01-01

    A model has been developed to simulate the annual dormancy cycle of seeds of light-requiring species in the seed bank and the germination of exhumed seeds after irradiation. Simulation of dormancy and germination is based on a physiological model concerning the action of phytochrome in the seed.

  6. On the role of abscisic acid in seed dormancy of red rice.

    Science.gov (United States)

    Gianinetti, Alberto; Vernieri, Paolo

    2007-01-01

    Abscisic acid (ABA) is commonly assumed to be the primary effector of seed dormancy, but conclusive evidence for this role is lacking. This paper reports on the relationships occurring in red rice between ABA and seed dormancy. Content of free ABA in dry and imbibed caryopses, both dormant and after-ripened, the effects of inhibitors, and the ability of applied ABA to revert dormancy breakage were considered. The results indicate: (i) no direct correlation of ABA content with the dormancy status of the seed, either dry or imbibed; (ii) different sensitivity to ABA of non-dormant seed and seed that was forced to germinate by fluridone; and (iii) an inability of exogenous ABA to reinstate dormancy in fluridone-treated seed, even though applied at a pH which favoured high ABA accumulation. These considerations suggest that ABA is involved in regulating the first steps of germination, but unidentified developmental effectors that are specific to dormancy appear to stimulate ABA synthesis and to enforce the responsiveness to this phytohormone. These primary effectors appear physiologically to modulate dormancy and via ABA they effect the growth of the embryo. Therefore, it is suggested that ABA plays a key role in integrating the dormancy-specific developmental signals with the control of growth.

  7. Effects of dormancy-breaking chemicals on ABA levels in barley grain embryos

    NARCIS (Netherlands)

    Wang, M.; Meulen, R.M. van der; Visser, K.; Schalk, H.P. van; Duijn, B. van; Boer, A.H. de

    1998-01-01

    The endogenous ABA contents of dormant and nondormant barley grains were determined following application of different compounds to break dormancy. The chemicals used for breaking of dormancy in intact dormant grains were weak and strong acids, alcohols,. hydrogen peroxide, cyanide, nitrate,

  8. Natural variation for seed longevity and seed dormancy are negatively correlated in Arabidopsis

    NARCIS (Netherlands)

    Nguyen, T.P.; Keizer, L.C.P.; Eeuwijk, van F.; Smeekens, S.C.M.; Bentsink, L.

    2012-01-01

    Dormancy is a state of metabolic arrest that facilitates the survival of organisms during environmental conditions incompatible with their regular course of life. Many organisms have deep dormant stages to promote an extended life span (increased longevity). In contrast, plants have seed dormancy

  9. Key genes involved in desiccation tolerance and dormancy across life forms

    NARCIS (Netherlands)

    Costa, M.C.D.; Farrant, Jill M.; Oliver, Melvin J.; Ligterink, Wilco; Buitink, Julia; Hilhorst, H.M.W.

    2016-01-01

    Desiccation tolerance (DT, the ability of certain organisms to survive severe dehydration) was a key trait in the evolution of life in terrestrial environments. Likely, the development of desiccation-tolerant life forms was accompanied by the acquisition of dormancy or a dormancy-like stage as a

  10. Regulation of seed dormancy by abscisic acid and DELAY OF Germination 1

    NARCIS (Netherlands)

    Dekkers, S.J.W.; Bentsink, L.

    2015-01-01

    Physiological dormancy has been described as a physiological inhibiting mechanism that prevents radicle emergence. It can be caused by the embryo (embryo dormancy) as well as by the structures that cover the embryo. One of its functions is to time plant growth and reproduction to the most optimal

  11. Maturation, temperature and breaking dormancy of Comanthera seeds

    Directory of Open Access Journals (Sweden)

    Andréa Santos Oliveira

    2016-09-01

    Full Text Available Given the importance of “everlasting” plants for their ornamental value and vulnerability to extractive practices, studies to ensure the propagation of the species are indispensable. The aim of this study was to assess whether there is an association between seed coat color and the quality of everlasting seeds, in the presence or absence of dormancy. Four species (Comanthera elegans, C. nitida, C. bisculata, and Comanthera sp. were separated with respect to seed coat color and underwent germination first count, germination, and germination speed index testing in a substrate moistened with water or 0.1% fluridone solution, in alternating temperatures of 10/25°C and 15/25°C. A completely randomized experimental design was used in a 4 x 2 x 2 factorial arrangement [seed coat color (green, beige, red, brown × temperature (10/25°C and 15/25°C × dormancy breaking (with or without]. In general, the alternating 15/25°C temperature is favorable for germination of everlasting plants. The use of fluridone is favorable to germination and seed vigor, especially when using the alternating temperature of 10/25°C. The effect of seed coat color varies among species; higher germination and vigor values are seen in green seeds for Comanthera sp. and lower values in C. bisculata. For C. nitida and C. elegans, seed coat color does not influence seed quality. Direct relationships between fluoridone efficiency in breaking dormancy of seeds of different species of everlasting plants and classification in different colors are not observed.

  12. A laboratory simulation of Arabidopsis seed dormancy cycling provides new insight into its regulation by clock genes and the dormancy-related genes DOG1, MFT, CIPK23 and PHYA.

    Science.gov (United States)

    Footitt, Steven; Ölçer-Footitt, Hülya; Hambidge, Angela J; Finch-Savage, William E

    2017-08-01

    Environmental signals drive seed dormancy cycling in the soil to synchronize germination with the optimal time of year, a process essential for species' fitness and survival. Previous correlation of transcription profiles in exhumed seeds with annual environmental signals revealed the coordination of dormancy-regulating mechanisms with the soil environment. Here, we developed a rapid and robust laboratory dormancy cycling simulation. The utility of this simulation was tested in two ways: firstly, using mutants in known dormancy-related genes [DELAY OF GERMINATION 1 (DOG1), MOTHER OF FLOWERING TIME (MFT), CBL-INTERACTING PROTEIN KINASE 23 (CIPK23) and PHYTOCHROME A (PHYA)] and secondly, using further mutants, we test the hypothesis that components of the circadian clock are involved in coordination of the annual seed dormancy cycle. The rate of dormancy induction and relief differed in all lines tested. In the mutants, dog1-2 and mft2, dormancy induction was reduced but not absent. DOG1 is not absolutely required for dormancy. In cipk23 and phyA dormancy, induction was accelerated. Involvement of the clock in dormancy cycling was clear when mutants in the morning and evening loops of the clock were compared. Dormancy induction was faster when the morning loop was compromised and delayed when the evening loop was compromised. © 2017 The Authors Plant, Cell & Environment Published by John Wiley & Sons Ltd.

  13. The Effect of Different Treatments on Seed Dormancy Breaking of Weed Stalked Bur Grass Tragus racemosus (L. AlI.

    Directory of Open Access Journals (Sweden)

    Gholam reza doraki

    2017-01-01

    observed under wet chilling treatment at 4°C for 4 weeds and the lowest one (6% was observed in control. The highest germination percentage under H2SO4 treatment was 41% obtained at the level of 80 seconds, under KNO3 treatment was 69% obtained at the level of 0.8%, and under GA3 treatment was 62% obtained at the level of 400 ppm. The highest germination rate (18.24 seeds per day was observed at KNO3 treatment (0.8% and the lowest one (0.91 seeds per day was observed in control. In addition, the highest germination rate under H 2SO4 treatment was 15.28 seeds per day obtained at the level of 80 seconds, under wet chilling was 13.25 seeds per day obtained at the level of 3 weeks, and under GA3 treatment was 12.08 seeds per day obtained at the level of 200 ppm. Wet chilling enhances the production of such stimulants as gibberellins. On the other hand, chilling treatment may reduce ABA amount or the sensitivity of embryo to ABA which can play a role in seeds dormancy breaking. KNO3 is likely to increase the sensitivity of germinating seeds to light acting as a complement factor for phytochrome which results in higher germination of the seeds. Most researchers believe that dormancy is broken by the balance between growth inhibitors like abscisic acid and growth stimulators like gibberellins. In addition, gibberellins activate a special signaling pathway that reduces abscisic acid in seeds and in contrast, auxins and cytokinins of the seeds are increased to a level enough for inducing dormancy break. Conclusion: In the present study, the germinated seeds were counted for 21 days. The highest germination percentage (76% was observed under wet chilling treatment for 4 weeks and the lowest one (6% was observed under control treatment. The highest germination rate (18.24 seeds per day was observed under KNO3treatment (0.8% and the lowest rate (0.91 seeds per day was reported under control treatment. According to the results it can be concluded that the dormancy of Stalked Bur Grass

  14. Gene expression profiles of Arabidopsis Cvi seeds during dormancy cycling indicate a common underlying dormancy control mechanism.

    Science.gov (United States)

    Cadman, Cassandra S C; Toorop, Peter E; Hilhorst, Henk W M; Finch-Savage, William E

    2006-06-01

    Physiologically dormant seeds, like those of Arabidopsis, will cycle through dormant states as seasons change until the environment is favourable for seedling establishment. This phenomenon is widespread in the plant kingdom, but has not been studied at the molecular level. Full-genome microarrays were used for a global transcript analysis of Arabidopsis thaliana (accession Cvi) seeds in a range of dormant and dry after-ripened states during cycling. Principal component analysis of the expression patterns observed showed that they differed in newly imbibed primary dormant seeds, as commonly used in experimental studies, compared with those in the maintained primary and secondary dormant states that exist during cycling. Dormant and after-ripened seeds appear to have equally active although distinct gene expression programmes, dormant seeds having greatly reduced gene expression associated with protein synthesis, potentially controlling the completion of germination. A core set of 442 genes were identified that had higher expression in all dormant states compared with after-ripened states. Abscisic acid (ABA) responsive elements were significantly over-represented in this set of genes the expression of which was enhanced when multiple copies of the elements were present. ABA regulation of dormancy was further supported by expression patterns of key genes in ABA synthesis/catabolism, and dormancy loss in the presence of fluridone. The data support an ABA-gibberelic acid hormone balance mechanism controlling cycling through dormant states that depends on synthetic and catabolic pathways of both hormones. Many of the most highly expressed genes in dormant states were stress-related even in the absence of abiotic stress, indicating that ABA, stress and dormancy responses overlap significantly at the transcriptome level.

  15. Platelet Proteome and Tumor Dormancy: Can Platelets Content Serve as Predictive Biomarkers for Exit of Tumors from Dormancy?

    Energy Technology Data Exchange (ETDEWEB)

    Almog, Nava, E-mail: nava.almog@tufts.edu; Klement, Giannoula Lakka, E-mail: nava.almog@tufts.edu [Center of Cancer Systems Biology, Caritas St. Elizabeth' s Medical Center, Tufts University School of Medicine, Boston, MA (United States)

    2010-05-11

    Although tumor dormancy is highly prevalent, the underling mechanisms are still mostly unknown. It is unclear which lesions will progress and become a disseminated cancer, and which will remain dormant and asymptomatic. Yet, an improved ability to predict progression would open the possibility of timely treatment and improvement in outcomes. We have recently described the ability of platelets to selectively uptake angiogenesis regulators very early in tumor growth, and proposed their use as an early marker of malignancy. In this review we will summarize current knowledge about these processes and will discuss the possibility of using platelet content to predict presence of occult tumors.

  16. Overcoming dormancy in seeds of cotton-silk tree

    Directory of Open Access Journals (Sweden)

    Irinaldo Lima do Nascimento

    2012-06-01

    Full Text Available Cotton-silk tree Ceiba glaziovii (kuntze k. Schu belongs to family Bombacaceas and is locally known as barriguda. It is widely used in landscaping and reforestation, neverdeless seed dormancy affects reproduction in this species. The objective of this study was to evaluate the effectiveness of different methods to overcome dormancy in the germination process. Treatments included mechanical scarification with 85-grit sandpaper, chemical scarification with concentrated sulfuric acid for 5, 10, 15 and 20 minutes, physical scarification with hot water at 60°, 70°, 80°and 90° C for one minute, imbibition in distilled water for 24, 48 and 72 hours, oven heating at 65° C for 1, 2, 3 and 4 hours, and a control treatment. Each treatment included four replicates of 25 seeds, using a completely randomized experimental design, and means were compared by the Scott-Knott test at the 5% probability level. Assessed parameters included emergence percentage, emergence rate index, dry matter and length of plants. The most recommended treatments were mechanical scarification, immersion in sulfuric acid for 5, 10 and 15 minutes and immersion in distilled water for 48 hours.

  17. Medicago Scutellata Seed Dormancy Breaking by Ultrasonic Waves

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    Nazari Meisam

    2014-12-01

    Full Text Available In this study dormancy breaking of a hard-coated plant seed, Medicago scutellata, was investigated. The ultrasonic waves effect on the seed germination percentage, germination rate, radicle length and stalk length growth was assessed. Six treatments of waves exposure periods including 0, 1, 3, 5, 7, and 9 minutes were tested under laboratorial conditions. Statistical analyses were done at probability level of 0.01. Results revealed that the ultrasonic waves have a significantly positive effect on the seed dormancy breaking, but there was no linear correlation between the increasing times of exposure with any of the growth features. The best treatment for germination percentage and germination rate was the 7-minute one and the 3-minute one was the best for radicle length growth. Treatments of 3, 5 and 7 minutes had the same effect on stalk length growth and were better than all other treatments. The 9-minute treatment had a negative effect, even lessening the growth of all of the assessed features in comparison with the control treatment.

  18. Methods to overcome dormancy in tree tomato (Solanum betaceum seeds

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    Carlos Kosera Neto

    2015-12-01

    Full Text Available The tree tomato (Solanum betaceum is a poorly known species that has fruits with great economic potential, as it can be consumed in natura or industrialized. However, for reaching this potential, it is necessary the development of technologies for seedlings production. The propagation of this species is mainly done by seeds, but the seed germination process is usually slow, especially under stress conditions. This study aimed at verifying whether tree tomato seeds have dormancy and which is the best method to obtain fast and uniform germination. A completely randomized design was adopted in a 5 x 2 factorial arrangement (methods to overcome dormancy x light, with four replications of 50 or 60 seeds, depending on the production cycle. The methods tested were cold stratification, hydropriming, priming with GA3 solution and control, with or without light. Seed germination and germination rate index, as well as the beginning and average time of germination, were also evaluated. The use of GA3 at a concentration of 100 mg L-1 or 300 mg L-1 is recommended to the germination of tree tomato seeds.

  19. Genetic and physiological characterization of two clusters of quantitative trait Loci associated with seed dormancy and plant height in rice.

    Science.gov (United States)

    Ye, Heng; Beighley, Donn H; Feng, Jiuhuan; Gu, Xing-You

    2013-02-01

    Seed dormancy and plant height have been well-studied in plant genetics, but their relatedness and shared regulatory mechanisms in natural variants remain unclear. The introgression of chromosomal segments from weedy into cultivated rice (Oryza sativa) prompted the detection of two clusters (qSD1-2/qPH1 and qSD7-2/qPH7) of quantitative trait loci both associated with seed dormancy and plant height. Together, these two clusters accounted for >96% of the variances for plant height and ~71% of the variances for germination rate in an isogenic background across two environments. On the initial introgression segments, qSD1-2/qPH1 was dissected genetically from OsVp1 for vivipary and qSD7-2/qPH7 separated from Sdr4 for seed dormancy. The narrowed qSD1-2/qPH1 region encompasses the semidwarf1 (sd1) locus for gibberellin (GA) biosynthesis. The qSD1-2/qPH1 allele from the cultivar reduced germination and stem elongation and the mutant effects were recovered by exogenous GA, suggesting that sd1 is a candidate gene of the cluster. In contrast, the effect-reducing allele at qSD7-2/qPH7 was derived from the weedy line; this allele was GA-insensitive and blocked GA responses of qSD1-2/qPH1, including the transcription of a GA-inducible α-amylase gene in imbibed endosperm, suggesting that qSD7-2/qPH7 may work downstream from qSD1-2/qPH1 in GA signaling. Thus, this research established the seed dormancy-plant height association that is likely mediated by GA biosynthesis and signaling pathways in natural populations. The detected association contributed to weed mimicry for the plant stature in the agro-ecosystem dominated by semidwarf cultivars and revealed the potential benefit of semidwarf genes in resistance to preharvest sprouting.

  20. Seed dormancy and germination of the medicinal holoparasitic plant Cistanche deserticola from the cold desert of northwest China.

    Science.gov (United States)

    Wang, Jia; Baskin, Jerry M; Baskin, Carol C; Liu, Guofang; Yang, Xuejun; Huang, Zhenying

    2017-06-01

    Cistanche deserticola is a holoparasitic plant with high medicinal value that reproduces only by seeds. However, the requirements for seed dormancy break and germination of this species remain unclear. The freshly matured dust-like seeds consist of a water-permeable seed coat and an undifferentiated oval-shaped embryo embedded in endosperm. No fresh seeds germinated in water or a 10 -5  M fluridone solution at any incubation temperature within 60 days. Length of embryos in seeds incubated in warm- and cold-started stratification sequences had increased 10.4 and 11.7% after 50 and 40 weeks, respectively. After 6 months, length of embryos in seeds stratified at 5 °C had increased by 12%. Germination of fresh seeds and of seeds stratified at 5 °C for 6 months and then incubated in mixed fluridone/gibberellic acid 3 (GA 3 ) solutions at 30/20 °C germinated to only 2.6 and 11.7%, respectively. Embryos of fresh seeds and of cold-stratified seeds had increased 29.4 and 15.8% in length, respectively, at the time of germination, but they never differentiated into organs. The highest germination (54.4%) was for seeds incubated in a 10 -5  M solution of fluridone in darkness in spring that had overwinter on the soil surface in the natural habitat. Our study indicates that breaking of physiological dormancy (PD) occurs first and then the embryo grows to a critical length (0.44 mm) without differentiation into organs prior to seed germination. Seeds for which PD had been broken were induced to germinate by fluridone and GA 3 at high temperature. Taken together, these results suggest that C. deserticola seeds have a specialized kind of morphophysiological dormancy. This study reveals possible ways to release seed dormancy that will be useful in propagating this medicinal species. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  1. Regulation of abscisic acid metabolism in relation to the dormancy and germination of cereal grains

    Directory of Open Access Journals (Sweden)

    Justyna Fidler

    2015-03-01

    Full Text Available Seed dormancy is of particular importance in the cultivation of cereals, as it directly affects the quality of crop yield. If the dormancy period is too short, this may lead to pre-harvest sprouting, whereas a dormancy period that is too long may cause uneven germination; both of these scenarios are associated with economic losses. Most enzymes engaged in the metabolism of abscisic acid (ABA have been identified, and significant progress has been made in understanding the role of this phytohormone in the induction and maintenance of dormancy, mainly as a result of research conducted in Arabidopsis. Much less is known about the metabolism and function of ABA in cereal grains, especially in relation to dormancy and germination. This review focuses on the regulation of ABA metabolism in dormant and non-dormant cereal grains, in both the dry state and upon imbibition. Moreover, this review describes the influence of factors such as after-ripening, light, temperature, nitric oxide, and reactive oxygen species (ROS on the dormancy and germination of cereal grains. These factors, with the exception of ROS, appear to affect the level of dormancy and germination of grains through regulation of ABA metabolism.

  2. Seed dormancy and germination vary within and among species of milkweeds

    Science.gov (United States)

    Kaye, Thomas N; Sandlin, Isaac J; Bahm, Matt A

    2018-01-01

    Abstract Pollinators in general and monarch butterflies in particular are in decline due to habitat loss. Efforts to restore habitats for insects that rely on specific plant groups as larvae or adults depend on the ability of practitioners to grow and produce these plants. Monarch larvae feed exclusively on milkweed species, primarily in the genus Asclepias, making propagation and restoration of these plants crucial for habitat restoration. Seed germination protocols for milkweeds are not well established, in part due to the large number of milkweed species and conflicting reports of seed dormancy in the genus. We tested for seed dormancy and the optimum period of cold stratification in 15 populations of A. speciosa and 1–2 populations of five additional species, including A. asperula, A. fascicularis, A. subulata, A. subverticillata and A. syriaca. We exposed seeds to cold (5 °C) moist conditions for 0, 2, 4, 6 and 8 weeks and then moved them to 15 °C/25 °C alternating temperatures. In A. speciosa, dormancy was detected in eight populations, and this dormancy was broken by 2–4 weeks of cold stratification. The remaining seven populations showed no dormancy. Seed dormancy was also detected in two populations of A. fascicularis (broken by 4–6 weeks of cold stratification) and a single population of A. syriaca (broken by 2 weeks of cold stratification). No dormancy was detected in A. asperula, A. subulata or A. subverticillata. Seed dormancy appears to be widespread in the genus (confirmed in 15 species) but can vary between populations even within the same species. Variation in seed dormancy and cold stratification requirements within and among Asclepias species suggests local adaptation and maternal environments may drive seedling ecology, and that growers should watch for low germination and use cold stratification as needed to maximize seed germination and retain genetic variability in restored populations. PMID:29593856

  3. Mitogen-Activated Protein Kinase Kinase 3 Regulates Seed Dormancy in Barley.

    Science.gov (United States)

    Nakamura, Shingo; Pourkheirandish, Mohammad; Morishige, Hiromi; Kubo, Yuta; Nakamura, Masako; Ichimura, Kazuya; Seo, Shigemi; Kanamori, Hiroyuki; Wu, Jianzhong; Ando, Tsuyu; Hensel, Goetz; Sameri, Mohammad; Stein, Nils; Sato, Kazuhiro; Matsumoto, Takashi; Yano, Masahiro; Komatsuda, Takao

    2016-03-21

    Seed dormancy has fundamental importance in plant survival and crop production; however, the mechanisms regulating dormancy remain unclear [1-3]. Seed dormancy levels generally decrease during domestication to ensure that crops successfully germinate in the field. However, reduction of seed dormancy can cause devastating losses in cereals like wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) due to pre-harvest sprouting, the germination of mature seed (grain) on the mother plant when rain occurs before harvest. Understanding the mechanisms of dormancy can facilitate breeding of crop varieties with the appropriate levels of seed dormancy [4-8]. Barley is a model crop [9, 10] and has two major seed dormancy quantitative trait loci (QTLs), SD1 and SD2, on chromosome 5H [11-19]. We detected a QTL designated Qsd2-AK at SD2 as the single major determinant explaining the difference in seed dormancy between the dormant cultivar "Azumamugi" (Az) and the non-dormant cultivar "Kanto Nakate Gold" (KNG). Using map-based cloning, we identified the causal gene for Qsd2-AK as Mitogen-activated Protein Kinase Kinase 3 (MKK3). The dormant Az allele of MKK3 is recessive; the N260T substitution in this allele decreases MKK3 kinase activity and appears to be causal for Qsd2-AK. The N260T substitution occurred in the immediate ancestor allele of the dormant allele, and the established dormant allele became prevalent in barley cultivars grown in East Asia, where the rainy season and harvest season often overlap. Our findings show fine-tuning of seed dormancy during domestication and provide key information for improving pre-harvest sprouting tolerance in barley and wheat. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Seed Anatomy and Water Uptake in Relation to Seed Dormancy in Opuntia tomentosa (Cactaceae, Opuntioideae)

    Science.gov (United States)

    Orozco-Segovia, A.; Márquez-Guzmán, J.; Sánchez-Coronado, M. E.; Gamboa de Buen, A.; Baskin, J. M.; Baskin, C. C.

    2007-01-01

    Background and Aims There is considerable confusion in the literature concerning impermeability of seeds with ‘hard’ seed coats, because the ability to take up (imbibe) water has not been tested in most of them. Seeds of Opuntia tomentosa were reported recently to have a water-impermeable seed coat sensu lato (i.e. physical dormancy), in combination with physiological dormancy. However, physical dormancy is not known to occur in Cactaceae. Therefore, the aim of this study was to determine if seeds of O. tomentosa are water-permeable or water-impermeable, i.e. if they have physical dormancy. Methods The micromorphology of the seed coat and associated structures were characterized by SEM and light microscopy. Permeability of the seed-covering layers was assessed by an increase in mass of seeds on a wet substrate and by dye-tracking and uptake of tritiated water by intact versus scarified seeds. Key Results A germination valve and a water channel are formed in the hilum–micropyle region during dehydration and ageing in seeds of O. tomentosa. The funicular envelope undoubtedly plays a role in germination of Opuntia seeds via restriction of water uptake and mechanical resistance to expansion of the embryo. However, seeds do not exhibit any of three features characteristic of those with physical dormancy. Thus, they do not have a water-impermeable layer(s) of palisade cells (macrosclereids) or a water gap sensu stricto and they imbibe water without the seed coat being disrupted. Conclusions Although dormancy in seeds of this species can be broken by scarification, they have physiological dormancy only. Further, based on information in the literature, it is concluded that it is unlikely that any species of Opuntia has physical dormancy. This is the first integrative study of the anatomy, dynamics of water uptake and dormancy in seeds of Cactaceae subfamily Opuntioideae. PMID:17298989

  5. Comparative Transcriptomes Profiling of Photoperiod-sensitive Male Sterile Rice Nongken 58S During the Male Sterility Transition between Short-day and Long-day

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    Zhu Yingguo

    2011-09-01

    Full Text Available Abstract Background Photoperiod-sensitive genic male sterile (PGMS rice, Nongken 58S, was discovered in 1973. It has been widely used for the production of hybrid rice, and great achievements have been made in improving rice yields. However, the mechanism of the male sterility transition in PGMS rice remains to be determined. Results To investigate the transcriptome during the male sterility transition in PGMS rice, the transcriptome of Nongken 58S under short-day (SD and long-day (LD at the glume primordium differentiation and pistil/stamen primordium forming stages was compared. Seventy-three and 128 differentially expressed genes (DEGs were identified at the glume primordium differentiation and pistil/stamen primordium forming stages, respectively. Five and 22 genes were markedly up-regulated (≥ 5-fold, and two and five genes were considerably down-regulated (≥ 5-fold under SD during the male sterility transition. Gene ontology annotation and pathway analysis revealed that four biological processes and the circadian rhythms and the flowering pathways coordinately regulated the male sterility transition. Further quantitative PCR analysis demonstrated that the circadian rhythms of OsPRR1, OsPRR37, OsGI, Hd1, OsLHY and OsDof in leaves were obviously different between Nongken 58S and Nongken 58 under LD conditions. Moreover, both OsPRR37 and Hd1 in the inflorescence displayed differences between Nongken 58S and Nongken 58 under both LD and SD conditions. Conclusion The results presented here indicate that the transcriptome in Nongken 58S was significantly suppressed under LD conditions. Among these DEGs, the circadian rhythm and the flowering pathway were involved in the male sterility transition. Furthermore, these pathways were coordinately involved in the male sterility transition in PGMS rice.

  6. The Rice Enhancer of Zeste [E(z] Genes SDG711 and SDG718 are respectively involved in Long Day and Short Day Signaling to Mediate the Accurate Photoperiod Control of Flowering time

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    Xiaoyun eLiu

    2014-10-01

    Full Text Available Recent advances in rice flowering studies have shown that the accurate control of flowering by photoperiod is regulated by key mechanisms that involve the regulation of flowering genes including Hd1, Ehd1, Hd3a, and RFT1. The chromatin mechanism involved in the regulation of rice flowering genes is presently not well known. Here we show that the rice E(z genes SDG711 and SDG718, which encode the Polycomb Repressive Complex2 (PRC2 key subunit that is required for trimethylation of histone H3 lysine 27 (H3K27me3, are respectively involved in long day (LD and short day (SD regulation of key flowering genes. The expression of SDG711 and SDG718 is induced by LD and SD, respectively. Over-expression and down-regulation of SDG711 respectively repressed and promoted flowering in LD, but had no effect in SD. By contrast, down-regulation of SDG718 had no effect in LD but delayed flowering in SD. SDG711 and SDG718 repressed OsLF (a repressor of Hd1 respectively in LD and SD, leading to a higher expression of Hd1 thus late flowering in LD and early flowering in SD. SDG711 was also found to be involved in the repression of Ehd1 in LD. SDG711 was shown to directly target to OsLF and Ehd1 loci to mediate H3K27me3 and gene repression. The function of the rice E(z genes in LD repression and SD promotion of flowering suggests that PRC2-mediated epigenetic repression of gene expression is involved in the accurate photoperiod control of rice flowering.

  7. Breast cancer and amyloid bodies: is there a role for amyloidosis in cancer-cell dormancy?

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    Mizejewski GJ

    2017-04-01

    Full Text Available Gerald J Mizejewski Wadsworth Center, New York State Department of Health, Albany, NY, USA Abstract: Breast cancer and Alzheimer’s disease (AD are major causes of death in older women. Interestingly, breast cancer occurs less frequently in AD patients than in the general population. Amyloidosis, the aggregation of amyloid proteins to form amyloid bodies, plays a central role in the pathogenesis of AD and other human neuropathies by forming intracellular fibrillary proteins. Contrary to popular belief, amyloidosis is a common occurrence in mammalian cells, and has recently been reported to be a natural physiological process in response to environmental stress stimulations (such as pH and temperature extremes, hypoxia, and oxidative stress. Many proteins contain an intrinsic “amyloid-converting motif”, which acts in conjunction with a specific noncoding RNA to induce formation of proteinaceous amyloid bodies that are stored in intracellular bundles. In cancer cells such as breast and prostate, the process of amyloidosis induces cells to enter a dormant or resting stage devoid of cell division and proliferation. Therefore, cancer cells undergo growth cessation and enter a dormant stage following amyloidosis in the cell; this is akin to giving the cell AD to cease growth. Keywords: α-fetoprotein, noncoding RNA, amyloid bodies, dormancy, breast cancer, Alzheimer’s disease

  8. Proteomic analysis of shoot tissue during photoperiod induced growth cessation in V. riparia Michx. grapevines

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    Victor Kim J

    2010-08-01

    Full Text Available Abstract Background Growth cessation, cold acclimation and dormancy induction in grapevines and other woody perennial plants native to temperate continental climates is frequently triggered by short photoperiods. The early induction of these processes by photoperiod promotes winter survival of grapevines in cold temperate zones. Examining the molecular processes, in particular the proteomic changes in the shoot, will provide greater insight into the signaling cascade that initiates growth cessation and dormancy induction. To begin understanding transduction of the photoperiod signal, Vitis riparia Michx. grapevines that had grown for 35 days in long photoperiod (long day, LD, 15 h were subjected to either a continued LD or a short photoperiod (short day, SD, 13 h treatment. Shoot tips (4-node shoot terminals were collected from each treatment at 7 and 28 days of LD and SD for proteomic analysis via two-dimensional (2D gel electrophoresis. Results Protein profiles were characterized in V. riparia shoot tips during active growth or SD induced growth cessation to examine physiological alterations in response to differential photoperiod treatments. A total of 1054 protein spots were present on the 2D gels. Among the 1054 proteins, 216 showed differential abundance between LD and SD (≥ two-fold ratio, p-value ≤ 0.05. After 7 days, 39 protein spots were more abundant in LD and 30 were more abundant in SD. After 28 days, 93 protein spots were more abundant in LD and 54 were more abundant in SD. MS/MS spectrometry was performed to determine the functions of the differentially abundant proteins. Conclusions The proteomics analysis uncovered a portion of the signal transduction involved in V. riparia grapevine growth cessation and dormancy induction. Different enzymes of the Calvin-Benson cycle and glutamate synthetase isoforms were more abundant either in LD or SD treatments. In LD tissues the significantly differentially more abundant proteins

  9. Proteomic analysis of shoot tissue during photoperiod induced growth cessation in V. riparia Michx. grapevines

    Science.gov (United States)

    2010-01-01

    Background Growth cessation, cold acclimation and dormancy induction in grapevines and other woody perennial plants native to temperate continental climates is frequently triggered by short photoperiods. The early induction of these processes by photoperiod promotes winter survival of grapevines in cold temperate zones. Examining the molecular processes, in particular the proteomic changes in the shoot, will provide greater insight into the signaling cascade that initiates growth cessation and dormancy induction. To begin understanding transduction of the photoperiod signal, Vitis riparia Michx. grapevines that had grown for 35 days in long photoperiod (long day, LD, 15 h) were subjected to either a continued LD or a short photoperiod (short day, SD, 13 h) treatment. Shoot tips (4-node shoot terminals) were collected from each treatment at 7 and 28 days of LD and SD for proteomic analysis via two-dimensional (2D) gel electrophoresis. Results Protein profiles were characterized in V. riparia shoot tips during active growth or SD induced growth cessation to examine physiological alterations in response to differential photoperiod treatments. A total of 1054 protein spots were present on the 2D gels. Among the 1054 proteins, 216 showed differential abundance between LD and SD (≥ two-fold ratio, p-value ≤ 0.05). After 7 days, 39 protein spots were more abundant in LD and 30 were more abundant in SD. After 28 days, 93 protein spots were more abundant in LD and 54 were more abundant in SD. MS/MS spectrometry was performed to determine the functions of the differentially abundant proteins. Conclusions The proteomics analysis uncovered a portion of the signal transduction involved in V. riparia grapevine growth cessation and dormancy induction. Different enzymes of the Calvin-Benson cycle and glutamate synthetase isoforms were more abundant either in LD or SD treatments. In LD tissues the significantly differentially more abundant proteins included flavonoid

  10. Seed storage-mediated dormancy alleviation in Fabaceae from campo rupestre

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    Naïla Nativel

    2015-09-01

    Full Text Available ABSTRACTWe studied the effects of seed storage on germination and dormancy alleviation in three species of Fabaceae endemic to campo rupestrein southeastern Brazil. Fresh seeds of Collaea cipoensis, Mimosa maguirei and Mimosa foliolosawere set to germinate and germination of seeds after four, five and 13 years of storage was tested. Seed viability was maintained for all species after the full storage period. Seed storage significantly increased germination percentage and decreased germination time for C. cipoensisand M. foliolosa, suggesting the alleviation of physical dormancy with storage. However, we did not find evidence of dormancy alleviation in M. maguirei since stored seeds showed a decrease in germination in comparison to that of fresh seeds. Our data indicate species-specific storage-mediated dormancy alleviation, which will have important implications for restoration of campo rupestre.

  11. The effects of temperature on the dormancy and germination of Cirsium arvense (L. Scop. seeds

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    Anna Bochenek

    2011-01-01

    Full Text Available The ecophysiological regulation of seed dormancy in perennial species and those with a varied life cycle has not been studied in detail yet. That is why an attempt has been made to determine the Cirsium arvense seed water relations during stratification and afterripening at different temperatures and germination at constant or fluctuating temperatures on the basis of the hydrotime model. The obtained results showed that breaking of the primary dormancy of achenes took place only during the first stratification month at moderate temperatures, mainly due to an increase in the average water-stress tolerance in a seed population. The induction of secondary seed dormancy during after-ripening at all temperatures resulted mostly from a substantial loss of the seeds' ability to tolerate water stress. Fluctuating temperatures affected neither seed germination nor the hydrotime model parameters. The analysis of the variations of hydrotime model parameters allows a better understanding of the physiological basis of seed dormancy relief and induction.

  12. Bud Dormancy in Perennial Fruit Tree Species: A Pivotal Role for Oxidative Cues

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    Rémi Beauvieux

    2018-05-01

    Full Text Available For perennial plants, bud dormancy is a crucial step as its progression over winter determines the quality of bud break, flowering, and fruiting. In the past decades, many studies, based on metabolic, physiological, subcellular, genetic, and genomic analyses, have unraveled mechanisms underlying bud dormancy progression. Overall, all the pathways identified are interconnected in a very complex manner. Here, we review early and recent findings on the dormancy processes in buds of temperate fruit trees species including hormonal signaling, the role of plasma membrane, carbohydrate metabolism, mitochondrial respiration and oxidative stress, with an effort to link them together and emphasize the central role of reactive oxygen species accumulation in the control of dormancy progression.

  13. Effect of ethanol and plant growth regulators on termination of potato microtuber dormancy

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    Wróbel Sławomir

    2015-12-01

    Full Text Available The duration of dormancy varies significantly among cultivars, but even short dormancy can limit usage of potato microtubers for seed production. The aim of the research was to test efficacy of dormancy breaking by treatment with an aqueous solution of ethyl alcohol, saccharose, gibberellic acid and kinetin (ethanol treatment in comparison to treatment with aqueous solution of thiourea, daminozide and gibberellic acid (standard treatment. Prolonging the period of microtuber production at the in vitro stage significantly favored the short-ening of the dormancy and facilitated its breaking. While the standard treatment had the strongest effect, the ethanol treatment was slightly less efficient. The statistically significant differences were only observed during the first 13 days after the microtuber treatment. After that time, efficacy of ethanol and standard treatments was similar to control treatment with water. The investigated treatments had no effect on the natural decrease of ABA level in microtubers.

  14. Genes controlling seed dormancy and pre-harvest sprouting in a rice-wheat-barley comparison

    DEFF Research Database (Denmark)

    Li, Chengdao; Ni, Peixiang; Francki, Michael

    2004-01-01

    Pre-harvest sprouting results in significant economic loss for the grain industry around the world. Lack of adequate seed dormancy is the major reason for pre-harvest sprouting in the field under wet weather conditions. Although this trait is governed by multiple genes it is also highly heritable....... A major QTL controlling both pre-harvest sprouting and seed dormancy has been identified on the long arm of barley chromosome 5H, and it explains over 70% of the phenotypic variation. Comparative genomics approaches among barley, wheat and rice were used to identify candidate gene(s) controlling seed...... dormancy and hence one aspect of pre-harvest sprouting. The barley seed dormancy/pre-harvest sprouting QTL was located in a region that showed good synteny with the terminal end of the long arm of rice chromosome 3. The rice DNA sequences were annotated and a gene encoding GA20-oxidase was identified...

  15. Chilling-Mediated DNA Methylation Changes during Dormancy and Its Release Reveal the Importance of Epigenetic Regulation during Winter Dormancy in Apple (Malus x domestica Borkh..

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    Gulshan Kumar

    Full Text Available Winter dormancy is a well known mechanism adopted by temperate plants, to mitigate the chilling temperature of winters. However, acquisition of sufficient chilling during winter dormancy ensures the normal phenological traits in subsequent growing period. Thus, low temperature appears to play crucial roles in growth and development of temperate plants. Apple, being an important temperate fruit crop, also requires sufficient chilling to release winter dormancy and normal phenological traits, which are often associated with yield and quality of fruits. DNA cytosine methylation is one of the important epigenetic modifications which remarkably affect the gene expression during various developmental and adaptive processes. In present study, methylation sensitive amplified polymorphism was employed to assess the changes in cytosine methylation during dormancy, active growth and fruit set in apple, under differential chilling conditions. Under high chill conditions, total methylation was decreased from 27.2% in dormant bud to 21.0% in fruit set stage, while no significant reduction was found under low chill conditions. Moreover, the demethylation was found to be decreased, while methylation increased from dormant bud to fruit set stage under low chill as compared to high chill conditions. In addition, RNA-Seq analysis showed high expression of DNA methyltransferases and histone methyltransferases during dormancy and fruit set, and low expression of DNA glcosylases during active growth under low chill conditions, which was in accordance with changes in methylation patterns. The RNA-Seq data of 47 genes associated with MSAP fragments involved in cellular metabolism, stress response, antioxidant system and transcriptional regulation showed correlation between methylation and their expression. Similarly, bisulfite sequencing and qRT-PCR analysis of selected genes also showed correlation between gene body methylation and gene expression. Moreover

  16. Chilling-Mediated DNA Methylation Changes during Dormancy and Its Release Reveal the Importance of Epigenetic Regulation during Winter Dormancy in Apple (Malus x domestica Borkh.).

    Science.gov (United States)

    Kumar, Gulshan; Rattan, Usha Kumari; Singh, Anil Kumar

    2016-01-01

    Winter dormancy is a well known mechanism adopted by temperate plants, to mitigate the chilling temperature of winters. However, acquisition of sufficient chilling during winter dormancy ensures the normal phenological traits in subsequent growing period. Thus, low temperature appears to play crucial roles in growth and development of temperate plants. Apple, being an important temperate fruit crop, also requires sufficient chilling to release winter dormancy and normal phenological traits, which are often associated with yield and quality of fruits. DNA cytosine methylation is one of the important epigenetic modifications which remarkably affect the gene expression during various developmental and adaptive processes. In present study, methylation sensitive amplified polymorphism was employed to assess the changes in cytosine methylation during dormancy, active growth and fruit set in apple, under differential chilling conditions. Under high chill conditions, total methylation was decreased from 27.2% in dormant bud to 21.0% in fruit set stage, while no significant reduction was found under low chill conditions. Moreover, the demethylation was found to be decreased, while methylation increased from dormant bud to fruit set stage under low chill as compared to high chill conditions. In addition, RNA-Seq analysis showed high expression of DNA methyltransferases and histone methyltransferases during dormancy and fruit set, and low expression of DNA glcosylases during active growth under low chill conditions, which was in accordance with changes in methylation patterns. The RNA-Seq data of 47 genes associated with MSAP fragments involved in cellular metabolism, stress response, antioxidant system and transcriptional regulation showed correlation between methylation and their expression. Similarly, bisulfite sequencing and qRT-PCR analysis of selected genes also showed correlation between gene body methylation and gene expression. Moreover, significant association

  17. Biology in the Dry Seed: Transcriptome Changes Associated with Dry Seed Dormancy and Dormancy Loss in the Arabidopsis GA-Insensitive sleepy1-2 Mutant

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    Sven K. Nelson

    2017-12-01

    Full Text Available Plant embryos can survive years in a desiccated, quiescent state within seeds. In many species, seeds are dormant and unable to germinate at maturity. They acquire the capacity to germinate through a period of dry storage called after-ripening (AR, a biological process that occurs at 5–15% moisture when most metabolic processes cease. Because stored transcripts are among the first proteins translated upon water uptake, they likely impact germination potential. Transcriptome changes associated with the increased seed dormancy of the GA-insensitive sly1-2 mutant, and with dormancy loss through long sly1-2 after-ripening (19 months were characterized in dry seeds. The SLY1 gene was needed for proper down-regulation of translation-associated genes in mature dry seeds, and for AR up-regulation of these genes in germinating seeds. Thus, sly1-2 seed dormancy may result partly from failure to properly regulate protein translation, and partly from observed differences in transcription factor mRNA levels. Two positive regulators of seed dormancy, DELLA GAI (GA-INSENSITIVE and the histone deacetylase HDA6/SIL1 (MODIFIERS OF SILENCING1 were strongly AR-down-regulated. These transcriptional changes appeared to be functionally relevant since loss of GAI function and application of a histone deacetylase inhibitor led to decreased sly1-2 seed dormancy. Thus, after-ripening may increase germination potential over time by reducing dormancy-promoting stored transcript levels. Differences in transcript accumulation with after-ripening correlated to differences in transcript stability, such that stable mRNAs appeared AR-up-regulated, and unstable transcripts AR-down-regulated. Thus, relative transcript levels may change with dry after-ripening partly as a consequence of differences in mRNA turnover.

  18. Dormancy effects on the reliability of nuclear thermal propulsion systems for long-term manned space missions

    International Nuclear Information System (INIS)

    Shooman, M.L.; Sforza, P.M.

    1993-01-01

    This paper explores the effects of dormancy on the reliability of a Nuclear Thermal Propulsion (NTP) system for long-term manned space missions, such as Mars exploration. Dormancy refers to the portion of space systems operation where the power and stress levels are significantly reduced from nominal values and the authors have identified dormancy as a significant effect. Three approaches are used to evaluate the relative importance of failure rates during dormant operation: use of failure rate models involving dormancy, power cycling and fully energized operation; study of data bases which include both dormant and energized failure rates; predictions based on an Arrhenius rate process formulation. The results of these approaches suggest that for a long term manned mission the dormancy, cycle, and energized failure rates will all be important. Reliability in the energized state normally receives utmost attention and care during design, however, unless equal attention is directed to dormancy, the mission reliability may be severely compromised

  19. Dormancy release and flowering time in Ziziphus jujuba Mill., a "direct flowering" fruit tree, has a facultative requirement for chilling.

    Science.gov (United States)

    Meir, Michal; Ransbotyn, Vanessa; Raveh, Eran; Barak, Simon; Tel-Zur, Noemi; Zaccai, Michele

    2016-03-15

    In deciduous fruit trees, the effect of chilling on flowering has mostly been investigated in the "indirect flowering" group, characterized by a period of rest between flower bud formation and blooming. In the present study, we explored the effects of chilling and chilling deprivation on the flowering of Ziziphus jujuba, a temperate deciduous fruit tree belonging to the "direct flowering" group, in which flower bud differentiation, blooming and fruit development occur after dormancy release, during a single growing season. Dormancy release, vegetative growth and flowering time in Z. jujuba cv. Ben-Li were assessed following several treatments of chilling. Chilling treatments quantitatively decreased the timing of vegetative bud dormancy release, thereby accelerating flowering, but had no effect on the time from dormancy release to flowering. Trees grown at a constant temperature of 25°C, without chilling, broke dormancy and flowered, indicating the facultative character of chilling in this species. We measured the expression of Z. jujuba LFY and AP1 homologues (ZjLFY and ZjAP1). Chilling decreased ZjLFY expression in dormant vegetative buds but had no effect on ZjAP1expression, which reached peak expression before dormancy release and at anthesis. In conclusion, chilling is not obligatory for dormancy release of Z. jujuba cv. Ben-Li vegetative buds. However, the exposure to chilling during dormancy does accelerate vegetative bud dormancy release and flowering. Copyright © 2016 Elsevier GmbH. All rights reserved.

  20. Tanned or burned: the role of fire in shaping physical seed dormancy.

    Science.gov (United States)

    Moreira, Bruno; Pausas, Juli G

    2012-01-01

    Plant species with physical seed dormancy are common in mediterranean fire-prone ecosystems. Because fire breaks seed dormancy and enhances the recruitment of many species, this trait might be considered adaptive in fire-prone environments. However, to what extent the temperature thresholds that break physical seed dormancy have been shaped by fire (i.e., for post-fire recruitment) or by summer temperatures in the bare soil (i.e., for recruitment in fire-independent gaps) remains unknown. Our hypothesis is that the temperature thresholds that break physical seed dormancy have been shaped by fire and thus we predict higher dormancy lost in response to fire than in response to summer temperatures. We tested this hypothesis in six woody species with physical seed dormancy occurring in fire-prone areas across the Mediterranean Basin. Seeds from different populations of each species were subject to heat treatments simulating fire (i.e., a single high temperature peak of 100 °C, 120 °C or 150 °C for 5 minutes) and heat treatments simulating summer (i.e., temperature fluctuations; 30 daily cycles of 3 hours at 31 °C, 4 hours at 43 °C, 3 hours at 33 °C and 14 hours at 18 °C). Fire treatments broke dormancy and stimulated germination in all populations of all species. In contrast, summer treatments had no effect over the seed dormancy for most species and only enhanced the germination in Ulex parviflorus, although less than the fire treatments. Our results suggest that in Mediterranean species with physical dormancy, the temperature thresholds necessary to trigger seed germination are better explained as a response to fire than as a response to summer temperatures. The high level of dormancy release by the heat produced by fire might enforce most recruitment to be capitalized into a single post-fire pulse when the most favorable conditions occur. This supports the important role of fire in shaping seed traits.

  1. Tanned or burned: the role of fire in shaping physical seed dormancy.

    Directory of Open Access Journals (Sweden)

    Bruno Moreira

    Full Text Available Plant species with physical seed dormancy are common in mediterranean fire-prone ecosystems. Because fire breaks seed dormancy and enhances the recruitment of many species, this trait might be considered adaptive in fire-prone environments. However, to what extent the temperature thresholds that break physical seed dormancy have been shaped by fire (i.e., for post-fire recruitment or by summer temperatures in the bare soil (i.e., for recruitment in fire-independent gaps remains unknown. Our hypothesis is that the temperature thresholds that break physical seed dormancy have been shaped by fire and thus we predict higher dormancy lost in response to fire than in response to summer temperatures. We tested this hypothesis in six woody species with physical seed dormancy occurring in fire-prone areas across the Mediterranean Basin. Seeds from different populations of each species were subject to heat treatments simulating fire (i.e., a single high temperature peak of 100 °C, 120 °C or 150 °C for 5 minutes and heat treatments simulating summer (i.e., temperature fluctuations; 30 daily cycles of 3 hours at 31 °C, 4 hours at 43 °C, 3 hours at 33 °C and 14 hours at 18 °C. Fire treatments broke dormancy and stimulated germination in all populations of all species. In contrast, summer treatments had no effect over the seed dormancy for most species and only enhanced the germination in Ulex parviflorus, although less than the fire treatments. Our results suggest that in Mediterranean species with physical dormancy, the temperature thresholds necessary to trigger seed germination are better explained as a response to fire than as a response to summer temperatures. The high level of dormancy release by the heat produced by fire might enforce most recruitment to be capitalized into a single post-fire pulse when the most favorable conditions occur. This supports the important role of fire in shaping seed traits.

  2. Cell signaling mechanisms and metabolic regulation of germination and dormancy in barley seeds

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    Zhenguo Ma

    2017-12-01

    Full Text Available During germination of barley (Hordeum vulgare L. seeds, important morphological and physiological changes take place, including development of organs and tissues and activation of metabolic pathways. Germination and dormancy of seeds are regulated by abscisic acid, gibberellins, reactive oxygen species (ROS, reactive nitrogen species (RNS and several other factors. Activities of ascorbate–glutathione cycle enzymes, responsible for scavenging ROS, strongly increase. Catalase and superoxide dismutase activities, also scavenging ROS, decrease at the onset of seed germination and then increase. With the increase in aerobic metabolism after radicle protrusion, the activities of the fermentation enzymes lactate and alcohol dehydrogenase decline rapidly. The RNS-scavenging activity of S-nitrosoglutathione reductase decreases in the course of seed germination, in concert with elevation of nitric oxide production and protein nitrosylation. This activity supports the role of RNS in regulating seed germination. Transcription of various genes at different phases of seed germination exhibits phase-specific changes. During imbibition, genes involved in cell wall metabolism are highly expressed; in the middle phase of seed germination before radicle protrusion, genes involved in amino acid synthesis, protein synthesis, and transport and nucleic acid synthesis are upregulated significantly, and after radicle protrusion, genes involved in photosynthetic metabolism are induced. In summary, signal transduction and metabolic regulation of seed germination involve diverse reactions and complex regulation at different levels of metabolic organization. Keywords: Seed germination, Reactive oxygen species, Reactive nitrogen species, Signal transduction, Gene expression

  3. Seed dormancy and germination in Jeffersonia dubia (Berberidaceae) as affected by temperature and gibberellic acid.

    Science.gov (United States)

    Rhie, Y H; Lee, S Y; Kim, K S

    2015-03-01

    The genus Jeffersonia, which contains only two species, has a trans-Atlantic disjunct distribution. The aims of this study were to determine the requirements for breaking dormancy and germination of J. dubia seeds and to compare its dormancy characteristics with those of the congener in eastern North America. Ripe seeds of J. dubia contain an underdeveloped embryo and were permeable to water. In nature, seeds were dispersed in May, while embryos began to grow in September, and were fully elongated by late November. Germination started in March of the next year, and seeds emerged as seedlings soon after germination. In laboratory experiments, incubation at high temperatures (25 °C, 25/15 °C) for at least 8 weeks was required to initiate embryo growth, while a transfer to moderate temperatures (20/10 °C, 15/6 °C) was needed for the completion of embryo growth. At least 8 weeks at 5 °C was effective in overcoming physiological dormancy and for germination in seeds after the embryos had fully elongated. Thus, both high and low temperatures were essential to break dormancy. Gibberellic acid (GA3 ) treatment could substitute for the high temperature requirement, but not for the low temperature requirement. Based on the dormancy-breaking requirements, it is confirmed that the seeds have deep simple morphophysiological dormancy. This dormancy type is similar to that of seeds of the eastern North American species J. diphylla. Although seeds require 10-11 months from seed dispersal to germination in nature, under controlled conditions they required only 3 months after treatment with 1000 mg·l(-1) GA3 , followed by incubation at 15/6 °C. This represents practical knowledge for propagation of these plants from seed. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  4. Dormancy overcome and seedling quality of pecan in nursery

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    Tales Poletto

    Full Text Available ABSTRACT: This study evaluated the efficiency of methods to overcome seed dormancy in different storage periods in the production of pecan seedlings. Seeds were submitted to the following treatments: T1, T4 and T7 - control treatments (seeds with no treatment, stored at room temperature for 30, 60 and 90 days, respectively, T2, T5 and T8 - stratification (seeds were distributed in boxes with wet sand maintained at a temperature of 4°C for 30, 60 and 90 days, respectively, T3, T6 and T9 - scarification + stratification (seeds scarified with sandpaper n.80 and stratified by 30, 60 and 90 days, respectively, in completely random experimental design. Plant height, stem diameter, number of leaves, full emergence and emergence speed index (ESI were evaluated after 14 weeks of sowing. The best development of pecan 'plants, their emergence, and ESI were observed in the stratification treatment for 90 day as well as in the scarification + stratification treatment for 90 day. Storing seeds in uncontrolled environment reduced their viability.

  5. OVERCOMING SEED DORMANCY IN Annona macroprophyllata AND Annona purpureaUSING PLANT GROWTH REGULATORS

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    GISELA FERREIRA

    Full Text Available ABSTRACT Some Annonaceae seeds are known to exhibit dormancy mechanisms ranging from possible seed coat impermeability to physiological dormancy. Thus, the aim of this study was to evaluate the effects of gibberellin (GA GA3 and GA4+7 + benzyladenine (GA4+7 + BA application in seeds of Annona macroprophyllata Donn. Sm (papausa and Annona purpurea Moc. & Sessé ex Dunal (chincuya. The experiment was performed by the application of GA3 and GA4+7 + BA on seeds in concentrations of 0, 200, 400, 500, 600, 800 and 1000 mg L-1. The regulators broke the dormancy of both species. However, application of the GA4+7 + BA mixture had more significant results, with greater increases in germination in A. macroprophyllata than in A. purpurea. Treatments that promoted the highest germinations were GA4+7 + BA at a concentration of 200 mg L-1 for A. macroprophyllata (77% and 200 mg L-1 of GA4+7 + BA and 500 mg L-1 of GA3 for A. purpurea (30% and 29%, respectively. Rate index, mean time and frequency of germination were distinct for both species and both treatments. Although both GA3 and GA4+7 + BA promote germination, the GA4+7 + BA mixture was more effective than GA3 to overcoming seed dormancy of both species, A. purpurea has a harder dormancy than A. macroprophyllata

  6. The Arabidopsis MYB96 transcription factor plays a role in seed dormancy.

    Science.gov (United States)

    Lee, Hong Gil; Lee, Kyounghee; Seo, Pil Joon

    2015-03-01

    Seed dormancy facilitates to endure environmental disadvantages by confining embryonic growth until the seeds encounter favorable environmental conditions for germination. Abscisic acid (ABA) and gibberellic acid (GA) play a pivotal role in the determination of the seed dormancy state. ABA establishes seed dormancy, while GA triggers seed germination. Here, we demonstrate that MYB96 contributes to the fine-tuning of seed dormancy regulation through the coordination of ABA and GA metabolism. The MYB96-deficient myb96-1 seeds germinated earlier than wild-type seeds, whereas delayed germination was observed in the activation-tagging myb96-1D seeds. The differences in germination rate disappeared after stratification or after-ripening. The MYB96 transcription factor positively regulates ABA biosynthesis genes 9-CIS-EPOXYCAROTENOID DIOXYGENASE 2 (NCED2), NCED5, NCED6, and NCED9, and also affects GA biosynthetic genes GA3ox1 and GA20ox1. Notably, MYB96 directly binds to the promoters of NCED2 and NCED6, primarily modulating ABA biosynthesis, which subsequently influences GA metabolism. In agreement with this, hyperdormancy of myb96-1D seeds was recovered by an ABA biosynthesis inhibitor fluridone, while hypodormancy of myb96-1 seeds was suppressed by a GA biosynthesis inhibitor paclobutrazol (PAC). Taken together, the metabolic balance of ABA and GA underlies MYB96 control of primary seed dormancy.

  7. Relationship between weed dormancy and herbicide rotations: implications in resistance evolution.

    Science.gov (United States)

    Darmency, Henri; Colbach, Nathalie; Le Corre, Valérie

    2017-10-01

    It is suggested that selection for late germinating seed cohorts is significantly associated with herbicide resistance in some cropping systems. In turn, it is conceivable that rotating herbicide modes of action selects for populations with mutations for increased secondary dormancy, thus partially overcoming the delaying effect of rotation on resistance evolution. Modified seed dormancy could affect management strategies - like herbicide rotation - that are used to prevent or control herbicide resistance. Here, we review the literature for data on seed dormancy and germination dynamics of herbicide-resistant versus susceptible plants. Few studies use plant material with similar genetic backgrounds, so there are few really comparative data. Increased dormancy and delayed germination may co-occur with resistance to ACCase inhibitors, but there is no clear-cut link with resistance to other herbicide classes. Population shifts are due in part to pleiotropic effects of the resistance genes, but interaction with the cropping system is also possible. We provide an example of a model simulation that accounts for genetic diversity in the dormancy trait, and subsequent consequences for various cropping systems. We strongly recommend adding more accurate and detailed mechanistic modelling to the current tools used today to predict the efficiency of prevention and management of herbicide resistance. These models should be validated through long-term experimental designs including mono-herbicide versus chemical rotation in the field. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  8. Molecular Mechanisms Underlying Abscisic Acid/Gibberellin Balance in the Control of Seed Dormancy and Germination in Cereals

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    Pham A. Tuan

    2018-05-01

    Full Text Available Seed dormancy is an adaptive trait that does not allow the germination of an intact viable seed under favorable environmental conditions. Non-dormant seeds or seeds with low level of dormancy can germinate readily under optimal environmental conditions, and such a trait leads to preharvest sprouting, germination of seeds on the mother plant prior to harvest, which significantly reduces the yield and quality of cereal crops. High level of dormancy, on the other hand, may lead to non-uniform germination and seedling establishment. Therefore, intermediate dormancy is considered to be a desirable trait as it prevents the problems of sprouting and allows uniformity of postharvest germination of seeds. Induction, maintenance, and release of seed dormancy are complex physiological processes that are influenced by a wide range of endogenous and environmental factors. Plant hormones, mainly abscisic acid (ABA and gibberellin (GA, are the major endogenous factors that act antagonistically in the control of seed dormancy and germination; ABA positively regulates the induction and maintenance of dormancy, while GA enhances germination. Significant progress has been made in recent years in the elucidation of molecular mechanisms regulating ABA/GA balance and thereby dormancy and germination in cereal seeds, and this review summarizes the current state of knowledge on the topic.

  9. Molecular Mechanisms Underlying Abscisic Acid/Gibberellin Balance in the Control of Seed Dormancy and Germination in Cereals

    Science.gov (United States)

    Tuan, Pham A.; Kumar, Rohit; Rehal, Pawanpuneet K.; Toora, Parneet K.; Ayele, Belay T.

    2018-01-01

    Seed dormancy is an adaptive trait that does not allow the germination of an intact viable seed under favorable environmental conditions. Non-dormant seeds or seeds with low level of dormancy can germinate readily under optimal environmental conditions, and such a trait leads to preharvest sprouting, germination of seeds on the mother plant prior to harvest, which significantly reduces the yield and quality of cereal crops. High level of dormancy, on the other hand, may lead to non-uniform germination and seedling establishment. Therefore, intermediate dormancy is considered to be a desirable trait as it prevents the problems of sprouting and allows uniformity of postharvest germination of seeds. Induction, maintenance, and release of seed dormancy are complex physiological processes that are influenced by a wide range of endogenous and environmental factors. Plant hormones, mainly abscisic acid (ABA) and gibberellin (GA), are the major endogenous factors that act antagonistically in the control of seed dormancy and germination; ABA positively regulates the induction and maintenance of dormancy, while GA enhances germination. Significant progress has been made in recent years in the elucidation of molecular mechanisms regulating ABA/GA balance and thereby dormancy and germination in cereal seeds, and this review summarizes the current state of knowledge on the topic. PMID:29875780

  10. Assessment of Seed Germination and Dormancy of Thirty Seeds Lots of

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    H.R Ehyaee

    2012-06-01

    Full Text Available Most seeds of medicinal plants due to ecological adaptation to environmental conditions have several types of dormancy. Hence, it's necessary to recognize ecological factors that affect dormancy and provide optimum conditions for germination in medicinal plant species. Thirty seed lots were used to estimate germination and dormancy of medicinal plants. Treatments were KNO3, (2% and scarification of seeds by sand paper, hypochlorite sodium and removing the seed coat with four replicates of 25 seeds. Maximum and minimum germination observed in H2O for Digitalis purpure 100% and Saponaria officinalis 0%. In KNO3 treatment, Portulaca oleracea had the highest germination of 91% and Hyocyamus niger had no any germinated seeds. In sand paper treatment, the Saponaria officinalis and Datura stramonium had maximum, 33% and minimum 0% germination respectively.

  11. Role of the lens in controlling physical dormancy break and germination of Delonix regia (Fabaceae: Caesalpinioideae).

    Science.gov (United States)

    Jaganathan, G K; Wu, G-R; Han, Y-Y; Liu, B L

    2017-01-01

    Physical dormancy occurs in all three subfamilies of Fabaceae, namely Mimosoideae, Papilionoideae and Caesalpinioideae, making it one of the largest plant families in terms of number of species with physical dormancy. However, little is known about the water gap structure and germination ecology of species in Caesalpinioideae. Freshly collected seeds of Delonix regia (Caesalpinioideae) did not imbibe water, thus they had physical dormancy. Both dry heat and wet heat were effective in breaking dormancy, however, longer duration was required at 80 °C and shorter duration at 90 °C. Seeds buried in the field for 2 years germinated to 21% and 42% after the first and second summer, respectively, compared with 3% germination in seeds at the time of maturity. Seeds incubated at 15/60 °C in the laboratory (mimicking summer conditions) for 3 months supported this conclusion, as dormancy was relieved in 18% and 24% of seeds stored dry and watered intermediately, respectively. All the dormancy breaking treatments resulted in lifting of palisade layers in the lens region to form a circular lid-like opening, i.e. water gap (Type II simple). Blocking experiments confirmed that water entered only through the lens and no secondary water entry point was observed. No apparent changes in morphology/anatomy of the hilum region were noted in dormant and non-dormant (water permeable) seeds. These results suggest that summer temperatures could open the lens in a proportion of seeds every year and that germination occurs during the subsequent wet season in the tropics. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  12. Physiological characteristics and related gene expression of after-ripening on seed dormancy release in rice.

    Science.gov (United States)

    Du, W; Cheng, J; Cheng, Y; Wang, L; He, Y; Wang, Z; Zhang, H

    2015-11-01

    After-ripening is a common method used for dormancy release in rice. In this study, the rice variety Jiucaiqing (Oryza sativa L. subsp. japonica) was used to determine dormancy release following different after-ripening times (1, 2 and 3 months). Germination speed, germination percentage and seedling emergence increased with after-ripening; more than 95% germination and 85% seedling emergence were observed following 1 month of after-ripening within 10 days of imbibition, compared with rice dormancy release. Dormancy release by after-ripening is mainly correlated with a rapid decline in ABA content and increase in IAA content during imbibition. Subsequently, GA(1)/ABA, GA(7)/ABA, GA(12)/ABA, GA(20)/ABA and IAA/ABA ratios significantly increased, while GA(3)/ABA, GA(4)/ABA and GAs/IAA ratio significantly decreased in imbibed seeds following 3 months of after-ripening, thereby altering α-amylase activity during seed germination. Peak α-amylase activity occurred at an earlier germination stage in after-ripened seeds than in freshly harvested seeds. Expression of ABA, GA and IAA metabolism genes and dormancy-related genes was regulated by after-ripening time upon imbibition. Expression of OsCYP707A5, OsGA2ox1, OsGA2ox2, OsGA2ox3, OsILR1, OsGH3-2, qLTG3-1 and OsVP1 increased, while expression of Sdr4 decreased in imbibed seeds following 3 months of after-ripening. Dormancy release through after-ripening might be involved in weakening tissues covering the embryo via qLTG3-1 and decreased ABA signalling and sensitivity via Sdr4 and OsVP1. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

  13. Pre-harvest Sprouting and Grain Dormancy in Sorghum bicolor: What Have We Learned?

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    Roberto L. Benech-Arnold

    2018-06-01

    Full Text Available The possibility of obtaining sorghum grains with quality to match the standards for a diversity of end-uses is frequently hampered by the susceptibility to pre-harvest sprouting (PHS displayed by many elite genotypes. For these reasons, obtaining resistance to PHS is considered in sorghum breeding programs, particularly when the crop is expected to approach harvest maturity under rainy or damp conditions prevalence. As in other cereals, the primary cause for sprouting susceptibility is a low dormancy prior to crop harvest; in consequence, most research has focused in understanding the mechanisms through which the duration of dormancy is differentially controlled in genotypes with contrasting sprouting behavior. With this aim two tannin-less, red-grained inbred lines were used as a model system: IS9530 (sprouting resistant and Redland B2 (sprouting susceptible. Redland B2 grains are able to germinate well before reaching physiological maturity (PM while IS9530 ones can start to germinate at 40–45 days after pollination, well after PM. Results show that the anticipated dormancy loss displayed by Redland B2 grains is related reduced embryo sensitivity to abscisic acid (ABA and increased levels of GA upon imbibition. In turn, transcriptional data showed that ABA signal transduction is impaired in Redland B2, which appears to have an impact on GA catabolism, thus affecting the overall GA/ABA balance that regulates germination. QTL analyses were conducted to test whether previous candidate genes were located in a dormancy QTL, but also to identify new genes involved in dormancy. These analyses yielded several dormancy QTL and one of them located in chromosome 9 (qGI-9 was consistently detected even across environments. Fine mapping is already in progress to narrow down the number of candidate genes in qGI-9.

  14. Combining drought survival via summer dormancy and annual biomass productivity in Dactylis glomerata L.

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    Rajae eKallida

    2016-02-01

    Full Text Available Under Mediterranean climates, the best strategy to produce rain-fed fodder crops is to develop perennial drought resistant varieties. Summer dormancy present in native germplasm has been shown to confer a high level of survival under severe drought. Nevertheless it has also been shown to be negatively correlated with annual biomass productivity. The aim of this study was to analyse the correlations between summer dormancy and annual biomass productivity related traits and to identify quantitative trait loci (QTL for these traits in a progeny of a summer dormant cocksfoot parent (Kasbah and a summer active parent (Medly. A total of 283 offspring and the parents were phenotyped for summer dormancy, plant growth rate and heading date in Morocco and for maximum leaf elongation rate (LERm in France. The individuals were genotyped with a total of 325 markers including 59 AFLP, 64 SSR and 202 DArT markers. The offspring exhibited a large quantitative variation for all measured traits. Summer dormancy showed a negative correlation with both plant growth rate (-0.34 p<0.005 and LERm (-0.27 p<0.005. However, genotypes with both a high level of summer dormancy and a high level of plant growth rate were detected in the progeny. One genetic map per parent was built with a total length of 377 and 423 cM for Kasbah and Medly, respectively. Both different and co-localised QTL for summer dormancy and plant growth rate were identified. These results demonstrate that it should be possible to create summer dormant cocksfoot varieties with a high annual biomass productivity.

  15. The role of the testa during development and in establishment of dormancy of the legume seed

    Science.gov (United States)

    Smýkal, Petr; Vernoud, Vanessa; Blair, Matthew W.; Soukup, Aleš; Thompson, Richard D.

    2014-01-01

    Timing of seed germination is one of the key steps in plant life cycles. It determines the beginning of plant growth in natural or agricultural ecosystems. In the wild, many seeds exhibit dormancy and will only germinate after exposure to certain environmental conditions. In contrast, crop seeds germinate as soon as they are imbibed usually at planting time. These domestication-triggered changes represent adaptations to cultivation and human harvesting. Germination is one of the common sets of traits recorded in different crops and termed the “domestication syndrome.” Moreover, legume seed imbibition has a crucial role in cooking properties. Different seed dormancy classes exist among plant species. Physical dormancy (often called hardseededness), as found in legumes, involves the development of a water-impermeable seed coat, caused by the presence of phenolics- and suberin-impregnated layers of palisade cells. The dormancy release mechanism primarily involves seed responses to temperature changes in the habitat, resulting in testa permeability to water. The underlying genetic controls in legumes have not been identified yet. However, positive correlation was shown between phenolics content (e.g., pigmentation), the requirement for oxidation and the activity of catechol oxidase in relation to pea seed dormancy, while epicatechin levels showed a significant positive correlation with soybean hardseededness. myeloblastosis family of transcription factors, WD40 proteins and enzymes of the anthocyanin biosynthesis pathway were involved in seed testa color in soybean, pea and Medicago, but were not tested directly in relation to seed dormancy. These phenolic compounds play important roles in defense against pathogens, as well as affecting the nutritional quality of products, and because of their health benefits, they are of industrial and medicinal interest. In this review, we discuss the role of the testa in mediating legume seed germination, with a focus on

  16. 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

  17. Epicotyl dormancy of tree peony as an oil plant broken by cyanamide

    Science.gov (United States)

    Xu, Jiajie; Gong, Mingfu; Liu, Fang; Wu, Sanlin; Liu, Xiaojie; Zhang, Ya; Xu, Gaoyu

    2018-04-01

    This test materials is `feng Dan', an oil peony, or tree peony as an oil plant, growing in Yangtze river basin. Impact of cyanamide on oil peony epicotyl dormancy was represented with germination rate of peony feeds, a-amylase activity, soluble sugar content, soluble protein content and peroxidase (POD) activity. Results showed that hypocotyls' dormancy of peony seeds was significant breaken by 0.3% cyanamide concentration. Alpha-amylase activity, soluble sugar content, soluble protein content and POD activity in 0.3% cyanamide concentration treatment was significantly higher than other treatments. There was no significant difference between the rest treatments.

  18. Arabidopsis Histone Demethylases LDL1 and LDL2 Control Primary Seed Dormancy by Regulating DELAY OF GERMINATION 1 and ABA Signaling-Related Genes

    Directory of Open Access Journals (Sweden)

    Ming lei Zhao

    2015-03-01

    Full Text Available Seed dormancy controls germination and plays a critical role in regulating the beginning of the life cycle of plants. Seed dormancy is established and maintained during seed maturation and is gradually broken during dry storage (after-ripening. The plant hormone abscisic acid (ABA and DELAY OF GERMINATION1 (DOG1 protein are essential regulators of seed dormancy. Recent studies revealed that chromatin modifications are also involved in the transcription regulation of seed dormancy. Here, we showed that two Arabidopsis histone demethylases, LYSINESPECIFIC DEMETHYLASE LIKE 1 and 2 (LDL1 and LDL2 act redundantly in repressing of seed dormancy. LDL1 and LDL2 are highly expressed in the early silique developing stage. The ldl1 ldl2 double mutant displays increased seed dormancy, whereas overexpression of LDL1 or LDL2 in Arabidopsis causes reduced dormancy. Furthermore, we showed that LDL1 and LDL2 repress the expression of seed dormancy-related genes, including DOG1, ABA2 and ABI3 during seed dormancy establishment. Furthermore, genetic analysis revealed that the repression of seed dormancy by LDL1 and LDL2 requires DOG1, ABA2 and ABI3. Taken together, our findings revealed that LDL1 and LDL2 play an essential role in seed dormancy.

  19. Genome-wide identification of WRKY family genes in peach and analysis of WRKY expression during bud dormancy.

    Science.gov (United States)

    Chen, Min; Tan, Qiuping; Sun, Mingyue; Li, Dongmei; Fu, Xiling; Chen, Xiude; Xiao, Wei; Li, Ling; Gao, Dongsheng

    2016-06-01

    Bud dormancy in deciduous fruit trees is an important adaptive mechanism for their survival in cold climates. The WRKY genes participate in several developmental and physiological processes, including dormancy. However, the dormancy mechanisms of WRKY genes have not been studied in detail. We conducted a genome-wide analysis and identified 58 WRKY genes in peach. These putative genes were located on all eight chromosomes. In bioinformatics analyses, we compared the sequences of WRKY genes from peach, rice, and Arabidopsis. In a cluster analysis, the gene sequences formed three groups, of which group II was further divided into five subgroups. Gene structure was highly conserved within each group, especially in groups IId and III. Gene expression analyses by qRT-PCR showed that WRKY genes showed different expression patterns in peach buds during dormancy. The mean expression levels of six WRKY genes (Prupe.6G286000, Prupe.1G393000, Prupe.1G114800, Prupe.1G071400, Prupe.2G185100, and Prupe.2G307400) increased during endodormancy and decreased during ecodormancy, indicating that these six WRKY genes may play a role in dormancy in a perennial fruit tree. This information will be useful for selecting fruit trees with desirable dormancy characteristics or for manipulating dormancy in genetic engineering programs.

  20. Dispersal, dormancy and life-history tradeoffs at the individual, population and species levels in southern African Asteraceae.

    Science.gov (United States)

    de Waal, Caroli; Anderson, Bruce; Ellis, Allan G

    2016-04-01

    Dispersal and dormancy are important risk-reducing strategies in unpredictable environments. Negative covariation between these strategies is theoretically expected, but empirical evidence is limited and inconsistent. Moreover, covariation may be affected by other life-history traits and may vary across levels of biological organization. We assessed dispersal (vertical fall time of fruits, a proxy for wind dispersal ability) and dormancy (germination fractions measured during germination trials) in populations of 15 annual and 12 perennial wind-dispersed species in six Asteraceae genera from South Africa. Dormancy was higher in annuals than in perennials, whereas fall time was largely determined by evolutionary history. Controlling for phylogeny, dispersal and dormancy was negatively associated across species and life-history categories. Negative covariation between dispersal and dormancy was not evident at either the individual level (except for seed heteromorphic species) or the population level. Our study provides rare empirical support for the theoretical expectation of tradeoffs between dormancy and the alternative risk-reducing strategies, perenniality and dispersal, but refutes the expectation of increased dispersability in perennials. Although negative covariation between dispersal and dormancy at the species level appears not to be a simple consequence of upscaling individual-level mechanistic tradeoffs, our findings suggest that selection for one strategy may constrain evolution of the other. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  1. Effect of pre-germination treatments on the dormancy breaking and ...

    African Journals Online (AJOL)

    The demand for bitter kola (Garcinia kola) is high in Nigeria market but the population of the species is low both in the wild and home gardens. Rapid deforestation, heavy exploitation in the natural forest and difficulties associated with its germination occasioned by seed dormancy have been blamed. The study on ...

  2. Inheritance of fresh seed dormancy in Spanish-type peanut ( Arachis ...

    African Journals Online (AJOL)

    Production and seed quality in peanut (Arachis hypogaea L.) can be reduced substantially by in situ germination under unpredictable rainfed environments. Inheritance of fresh seed dormancy in Spanish x Spanish crosses was studied with two sets of segregating populations, an F2 population derived from true F1 hybrids ...

  3. Influence of the testa on seed dormancy, germination and longevity in Arabidopsis

    NARCIS (Netherlands)

    Debeaujon, I.; Léon-Kloosterziel, K.M.; Koornneef, M.

    2000-01-01

    The testa of higher plant seeds protects the embryo against adverse environmental conditions. Its role is assumed mainly by controlling germination through dormancy imposition and by limiting the detrimental activity of physical and biological agents during seed storage. To analyze the function of

  4. Differentially expressed genes associated with dormancy or germination of Arabidopsis thaliana seeds

    NARCIS (Netherlands)

    Toorop, P.E.; Barroco, R.M.; Engler, G.; Groot, S.P.C.; Hilhorst, H.W.M.

    2005-01-01

    Differential display analysis using dormant and non-dormant Arabidopsis thaliana (L.) Heynh seeds resulted in a set of genes that were associated with either dormancy or germination. Expression of the germination-associated genes AtRPL36B and AtRPL27B, encoding two ribosomal proteins, was

  5. Identification and functional analyses of genes regulating seed dormancy, longevity and germination

    NARCIS (Netherlands)

    Yazdanpanah, Farzaneh

    2018-01-01

    Fundamental knowledge about the processes affecting seed performance, including the regulation of germination, dormancy and longevity can provide insight to improve these traits, which is of economic importance for agricultural use and storage of seed crops. Accordingly, the objective of this

  6. QTL analysis of seed dormancy in Arabidopsis using recombinant inbred lines and MQM mapping

    NARCIS (Netherlands)

    Schaar, Wybe van der; Alonso-Blanco, Carlos; Léon-Kloosterziel, Karen M.; Jansen, Ritsert C.; Ooijen, Johan W. van; Koornneef, Maarten

    1997-01-01

    The genetic differences for seed germination between two commonly used Arabidopsis thaliana ecotypes Ler and Col, both showing a low level of seed dormancy, were investigated. The analysis was performed with 98 recombinant inbred lines (RILs) derived from the cross between the two ecotypes, and

  7. Improve germination of caper (Capparis Spinosa l. seeds by different induction treatments of seed dormancy breaking

    Directory of Open Access Journals (Sweden)

    M. R. Labbafi

    2018-03-01

    Full Text Available Seed dormancy is a common phase of the plant life cycle; different treatments can be used for breaking dormancy. The aim of this study was to find the best treatment for breaking dormancy and improve germination of caper (Capparis spinosa L.. This study based on the completely randomized design (CRD with 3 replications was done at research Laboratory of Medicinal Plants Institute, ACECR, Karaj, Iran. After different induction treatments containing different levels of potassium nitrate (KNO3, GA3, soaking and soaking with runner water, sulfuric acid, thidiazuron, and benzyl amino-purine, seeds were placed in Petri-dishes and incubated in two temperature regimes, first at fixed 20 ͦC, and second, alternate between 20 and 30 ͦC. The result showed that the germination percentage and germination rate of caper increased up to 75% and 1.35 respectively when the seeds treated with sulfuric acid for 15 min, and 2000 ppm GA3 under alternate 20-30 ͦC temperatures. Caper seed dormancy is mainly due to the inhibitors and hard seed coat that it prevents seed germination.

  8. The effect of environmental conditions on the seasonal dormancy pattern and germination of weed seeds

    NARCIS (Netherlands)

    Bouwmeester, H.J.

    1990-01-01

    Weeds cause considerable losses in horticultural and agricultural crops. Weeds are still predominantly controlled with herbicides. To reduce the use of chemicals, a better understanding of the biology of weeds is required. In this thesis the effect of environmental conditions on dormancy

  9. Evolution with a seed bank: The population genetic consequences of microbial dormancy.

    Science.gov (United States)

    Shoemaker, William R; Lennon, Jay T

    2018-01-01

    Dormancy is a bet-hedging strategy that allows organisms to persist through conditions that are suboptimal for growth and reproduction by entering a reversible state of reduced metabolic activity. Dormancy allows a population to maintain a reservoir of genetic and phenotypic diversity (i.e., a seed bank) that can contribute to the long-term survival of a population. This strategy can be potentially adaptive and has long been of interest to ecologists and evolutionary biologists. However, comparatively little is known about how dormancy influences the fundamental evolutionary forces of genetic drift, mutation, selection, recombination, and gene flow. Here, we investigate how seed banks affect the processes underpinning evolution by reviewing existing theory, implementing novel simulations, and determining how and when dormancy can influence evolution as a population genetic process. We extend our analysis to examine how seed banks can alter macroevolutionary processes, including rates of speciation and extinction. Through the lens of population genetic theory, we can understand the extent that seed banks influence the evolutionary dynamics of microorganisms as well as other taxa.

  10. VARIABILITY IN THEIR RELATIVE DORMANCY OF Lithraea molleoides (Vell. Eng. DIASPORES

    Directory of Open Access Journals (Sweden)

    Ana Paula de Aguiar Berger

    2014-06-01

    Full Text Available http://dx.doi.org/10.5902/1980509814570The large diversity of Anacardiaceae diaspores morphology has a notable repercussion in the processes of germination and emergence besides generating a differentiated behavior among the species. In this family, there are some species that present physical dormancy, some others present mechanical dormancy, others present no dormancy at all and some of them have no information detailed in the available literature. Lithraea molleoides (Vell. Eng. is one of the species which little is known regarding to dormancy. Therefore, the objective was to evaluate the germination and the emergence processes of seedlings from diaspores of this species collected in Araguari river valley, in the state of Minas Gerais, as well as to quantify the variability of dormancy intensity present among different individuals of the population. The diaspores were collected in October and November of 2004 and 2005, from six matrixes. Two experiments were set up. The germination experiment was conducted under controlled conditions and the emergence experiment was conducted in a semi-open greenhouse. Data was collected every 24 hours, up serving the protrusion of the embryo in the experiment setup in the laboratory, and the emergence of the hypocotyl of the seedling above the substrate in the experiment kept in the greenhouse. In both experiments, the diaspores originated from plant number two were more notable to some extent, having superior physiological quality compared to the others (average time between 4 and 22 days; average speeds between 0.042 and 0.0217 days-1; uncertainty between 1.62 and 3.5 bits and synchrony between 0.04 and 0.381. The high uncertainty values and the low synchrony values indicate that the germination and emergence processes of the Lithraea molleoides seedlings are spread in time, which allows us to characterize them as bearers of relative dormancy, although its intensity is variable among individuals of the

  11. On the language and physiology of dormancy and quiescence in plants.

    Science.gov (United States)

    Considine, Michael J; Considine, John A

    2016-05-01

    The language of dormancy is rich and poetic, as researchers spanning disciplines and decades have attempted to understand the spell that entranced 'Sleeping Beauty', and how she was gently awoken. The misleading use of 'dormancy', applied to annual axillary buds, for example, has confounded progress. Language is increasingly important as genetic and genomic approaches become more accessible to species of agricultural and ecological importance. Here we examine how terminology has been applied to different eco-physiological states in plants, and with pertinent reference to quiescent states described in other domains of life, in order to place plant quiescence and dormancy in a more complete context than previously described. The physiological consensus defines latency or quiescence as opportunistic avoidance states, where growth resumes in favourable conditions. In contrast, the dormant state in higher plants is entrained in the life history of the organism. Competence to resume growth requires quantitative and specific conditioning. This definition applies only to the embryo of seeds and specialized meristems in higher plants; however, mechanistic control of dormancy extends to mobile signals from peripheral tissues and organs, such as the endosperm of seed or subtending leaf of buds. The distinction between dormancy, quiescence, and stress-hardiness remains poorly delineated, most particularly in buds of winter perennials, which comprise multiple meristems of differing organogenic states. Studies in seeds have shown that dormancy is not a monogenic trait, and limited study has thus far failed to canalize dormancy as seen in seeds and buds. We argue that a common language, based on physiology, is central to enable further dissection of the quiescent and dormant states in plants. We direct the topic largely to woody species showing a single cycle of growth and reproduction per year, as these bear the majority of global timber, fruit, and nut production, as well being

  12. Involvement of ABA in induction of secondary dormancy in barley (Hordeum vulgare L.) seeds.

    Science.gov (United States)

    Leymarie, Juliette; Robayo-Romero, Maria Emilia; Gendreau, Emmanuel; Benech-Arnold, Roberto L; Corbineau, Françoise

    2008-12-01

    At harvest, barley seeds are dormant because their germination is difficult above 20 degrees C. Incubation of primary dormant seeds at 30 degrees C, a temperature at which they do not germinate, results in a loss of their ability to germinate at 20 degrees C. This phenomenon which corresponds to an induction of a secondary dormancy is already observed after a pre-treatment at 30 degrees C as short as 4-6 h, and is optimal after 24-48 h. It is associated with maintenance of a high level of embryo ABA content during seed incubation at 30 degrees C, and after seed transfer at 20 degrees C, while ABA content decreases rapidly in embryos of primary dormant seeds placed directly at 20 degrees C. Induction of secondary dormancy also results in an increase in embryo responsiveness to ABA at 20 degrees C. Application of ABA during seed treatment at 30 degrees C has no significant additive effect on the further germination at 20 degrees C. In contrast, incubation of primary dormant seeds at 20 degrees C for 48 and 72 h in the presence of ABA inhibits further germination on water similarly to 24-48 h incubation at 30 degrees C. However fluridone, an inhibitor of ABA synthesis, applied during incubation of the grains at 30 degrees C has only a slight effect on ABA content and secondary dormancy. Expression of genes involved in ABA metabolism (HvABA8'OH-1, HvNCED1 and HvNCED2) was studied in relation to the expression of primary and secondary dormancies. The results presented suggest a specific role for HvNCED1 and HvNCED2 in regulation of ABA synthesis in secondary seed dormancy.

  13. Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests

    Energy Technology Data Exchange (ETDEWEB)

    He, Yujie [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Yang, Jinyan [Univ. of Georgia, Athens, GA (United States). Warnell School of Forestry and Natural Resources; Northeast Forestry Univ., Harbin (China). Center for Ecological Research; Zhuang, Qianlai [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Purdue Univ., West Lafayette, IN (United States). Dept. of Agronomy; Harden, Jennifer W. [U.S. Geological Survey, Menlo Park, CA (United States); McGuire, Anthony D. [Alaska Cooperative Fish and Wildlife Research Unit, U.S. Geological Survey, Univ. of Alaska, Fairbanks, AK (United States). U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit; Liu, Yaling [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Wang, Gangsheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Climate Change Science Inst. and Environmental Sciences Division; Gu, Lianhong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division

    2015-11-20

    Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here in this study we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal-spatial scales. The dormancy model consistently produced better match with field-observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (<2% of soil organic carbon) and soil RH (7.5 ± 2.4 PgCyr-1). Spatial correlation analysis showed that soil organic carbon content was the dominating factor (correlation coefficient = 0.4-0.6) in the simulated spatial pattern of soil RH with both models. In contrast to strong temporal and local controls of soil temperature and moisture on microbial dormancy, our modeling results showed that soil carbon-to-nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = -0.43 to -0.58), indicating scale-dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial-based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.

  14. Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests

    Science.gov (United States)

    He, Yujie; Yang, Jinyan; Zhuang, Qianlai; Harden, Jennifer W.; McGuire, A. David; Liu, Yaling; Wang, Gangsheng; Gu, Lianhong

    2015-01-01

    Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal-spatial scales. The dormancy model consistently produced better match with field-observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (analysis showed that soil organic carbon content was the dominating factor (correlation coefficient = 0.4–0.6) in the simulated spatial pattern of soil RHwith both models. In contrast to strong temporal and local controls of soil temperature and moisture on microbial dormancy, our modeling results showed that soil carbon-to-nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = −0.43 to −0.58), indicating scale-dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial-based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.

  15. Characterization of PDF1 and its interaction with DELAY OF GERMINATION1 (DOG1) in the control of seed dormancy in Arabidopsis thaliana

    OpenAIRE

    Miatton, Emma

    2012-01-01

    Seed dormancy is defined as the incapacity of a viable seed to germinate under favourable conditions. It is established during seed maturation and reaches high levels in mature dry seeds. Dormancy is a complex adaptive trait that assures germination at proper time of the year at the onset of the favourable growing season. This trait is regulated by hormonal and environmental cues such as temperature and light. In Arabidopsis thaliana dormancy can be released by imbibing seeds at cold temperat...

  16. Produção de cebola de dias curtos no Alentejo. Influência da adubação localizada Short-day onion bulb yield in Alentejo. Influence of fertilizer band placement

    Directory of Open Access Journals (Sweden)

    Rui Manuel Almeida Machado

    2008-12-01

    Full Text Available As baixas temperaturas e o fácil encharcamento da maioria dos solos do Alentejo constituem uma restrição à produção de hortícolas ao ar livre, no Outono-Inverno. A cebola de dias curtos pode constituir uma opção pela sua capacidade para superar estes constrangimentos. Assim, este trabalho teve como objectivo estudar o comportamento de duas cultivares de cebola de dias curtos, plantadas no Outono e a influência da localização da adubação aquando da plantação. O ensaio decorreu na herdade experimental da Mitra da Universidade de Évora e os tratamentos em estudo foram: a cultivar de cebola de dias curtos (“Spring Star” e “Mineutaka” e o método de aplicação do adubo à plantação (distribuição a lanço e localização do adubo numa faixa a 10 cm ± 2 de profundidade, sob a linha de cultura. A adubação localizada não afectou a densidade radical (cm cm-3 sob a linha de cultura, nem a produção comercial de bolbos a qual foi respectivamente para a “Spring Star” e “Mineutaka” de 8,3 e 9,0 kg m-2. Visto as cultivares estudadas terem apresentado resistência ao excesso de água e às baixas temperaturas que ocorreram durante o ciclo, com produções consideráveis, a cebola de dias curtos apresenta-se como uma cultura com elevado potencial agronómico para o Alentejo. Adicionalmente, dada a época em que é realizada a cultura a água para a rega não será um factor limitante.In Alentejo region low temperatures and soil waterlogging during Autumn- Winter season are limiting factors for vegetable production under field conditions. Short -day onions can be an option to surpass these restrictions. The aim of the present work was to evaluate the effect of short - day onion cultivars and band placement of the fertilizer on onion production in Alentejo, planted during the autumn. The experiment was carried out at Mitra Research Station of the University of Évora and the treatments were: short - day onion cultivars (

  17. NITRIC OXIDE IMPLICATION IN THE CONTROL OF SEED DORMANCY AND GERMINATION

    Directory of Open Access Journals (Sweden)

    Erwann eArc

    2013-09-01

    Full Text Available Germination ability is regulated by a combination of environmental and endogenous signals with both synergistic and antagonistic effects. Nitric oxide (NO is a potent dormancy-releasing agent in many species, including Arabidopsis, and has been suggested to behave as an endogenous regulator of this physiological blockage. Distinct reports have also highlighted a positive impact of NO on seed germination under sub-optimal conditions. However, its molecular mode of action in the context of seed biology remains poorly documented. This review aims to focus on the implications of this radical in the control of seed dormancy and germination. The consequences of NO chemistry on the investigations on both its signaling and its targets in seeds are discussed. NO-dependant protein post-translational modifications are proposed as a key mechanism underlying NO signalling during early seed germination.

  18. Response of sunflower to various pre-germination techniques for breaking seed dormancy

    International Nuclear Information System (INIS)

    Nasreen, S.; Khan, M.A.; Uddin, S.

    2015-01-01

    Seed dormancy is considered to be a serious constraint in sunflower seed production. Viable seeds sometimes do not germinate even in the presence of favorable environmental conditions. Such seeds are suspected to be dormant. The study was conducted under controlled/laboratory conditions during spring 2010 at National Agricultural Research Centre, Islamabad. The objective of the study was to evaluate some techniques to convert a seed from dormant to non-dormant germinable state. Dormant seeds of 21 sunflower hybrids were treated with three hot water treatments (100/80 degree C) and four chemicals potassium nitrate, 0.2%, thiourea, 0.5%, ethanol, 25%, acetone, 25% for breaking seed dormancy .The untreated seed was taken as control. Soaking seeds in hot water (80 degree C) for 15 minutes followed by one day dry and seed treatment with acetone were found to be the most effective and successful techniques in converting the seed from dormant to non-dormant state. (author)

  19. Induction of 9-cis-epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy

    OpenAIRE

    Martínez-Andújar, Cristina; Ordiz, M. Isabel; Huang, Zhonglian; Nonogaki, Mariko; Beachy, Roger N.; Nonogaki, Hiroyuki

    2011-01-01

    Full understanding of mechanisms that control seed dormancy and germination remains elusive. Whereas it has been proposed that translational control plays a predominant role in germination, other studies suggest the importance of specific gene expression patterns in imbibed seeds. Transgenic plants were developed to permit conditional expression of a gene encoding 9-cis-epoxycarotenoid dioxygenase 6 (NCED6), a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, using the ecdysone recept...

  20. Breaking primary seed dormancy in Gibbens' beardtongue (Penstemon gibbensii) and blowout penstemon (Penstemon haydenii)

    Science.gov (United States)

    Kassie L. Tilini; Susan E. Meyer; Phil S. Allen

    2016-01-01

    This study established that chilling removes primary seed dormancy in 2 rare penstemons of the western US, Gibbens’ beardtongue (Penstemon gibbensii Dorn [Scrophulariaceae]) and blowout penstemon (Penstemon haydenii S. Watson). Wild-harvested seeds were subjected either to moist chilling at 2 to 4 °C (36-39 °F) for 0, 4, 8, 12, and 16 wk or to approximately 2 y of dry...

  1. Cancer cells enter dormancy after cannibalizing mesenchymal stem/stromal cells (MSCs).

    Science.gov (United States)

    Bartosh, Thomas J; Ullah, Mujib; Zeitouni, Suzanne; Beaver, Joshua; Prockop, Darwin J

    2016-10-18

    Patients with breast cancer often develop malignant regrowth of residual drug-resistant dormant tumor cells years after primary treatment, a process defined as cancer relapse. Deciphering the causal basis of tumor dormancy therefore has obvious therapeutic significance. Because cancer cell behavior is strongly influenced by stromal cells, particularly the mesenchymal stem/stromal cells (MSCs) that are actively recruited into tumor-associated stroma, we assessed the impact of MSCs on breast cancer cell (BCC) dormancy. Using 3D cocultures to mimic the cellular interactions of an emerging tumor niche, we observed that MSCs sequentially surrounded the BCCs, promoted formation of cancer spheroids, and then were internalized/degraded through a process resembling the well-documented yet ill-defined clinical phenomenon of cancer cell cannibalism. This suspected feeding behavior was less appreciable in the presence of a rho kinase inhibitor and in 2D monolayer cocultures. Notably, cannibalism of MSCs enhanced survival of BCCs deprived of nutrients but suppressed their tumorigenicity, together suggesting the cancer cells entered dormancy. Transcriptome profiles revealed that the resulting BCCs acquired a unique molecular signature enriched in prosurvival factors and tumor suppressors, as well as inflammatory mediators that demarcate the secretome of senescent cells, also referred to as the senescence-associated secretory phenotype. Overall, our results provide intriguing evidence that cancer cells under duress enter dormancy after cannibalizing MSCs. Importantly, our practical 3D coculture model could provide a valuable tool to understand the antitumor activity of MSCs and cell cannibalism further, and therefore open new therapeutic avenues for the prevention of cancer recurrence.

  2. Metagenomic analysis of buffalo rumen microbiome: Effect of roughage diet on Dormancy and Sporulation genes.

    Science.gov (United States)

    Singh, K M; Reddy, B; Patel, A K; Panchasara, H; Parmar, N; Patel, A B; Shah, T M; Bhatt, V D; Joshi, C G

    2014-12-01

    Buffalo rumen microbiome experiences a variety of diet stress and represents reservoir of Dormancy and Sporulation genes. However, the information on genomic responses to such conditions is very limited. The Ion Torrent PGM next generation sequencing technology was used to characterize general microbial diversity and the repertoire of microbial genes present, including genes associated with Dormancy and Sporulation in Mehsani buffalo rumen metagenome. The research findings revealed the abundance of bacteria at the domain level and presence of Dormancy and Sporulation genes which were predominantly associated with the Clostridia and Bacilli taxa belonging to the phyla Firmicutes. Genes associated with Sporulation cluster and Sporulation orphans were increased from 50% to 100% roughage treatment, thereby promoting sporulation all along the treatments. The spore germination is observed to be the highest in the 75% roughage treatment both in the liquid and solid rumen fraction samples with respect to the decrease in the values of the genes associated with spore core dehydration, thereby facilitating spore core hydration which is necessary for spore germination.

  3. Dormancy break with garlic extract and hydrogen peroxide in rootstock vine ‘SO4’

    Directory of Open Access Journals (Sweden)

    Aguilla Juan Saavedra del

    2016-01-01

    Full Text Available A synthetic product is used to help overcome dormancy of the buds of vines in tropical and sub-tropical climate, but the product currently available in Brazil has the highest level of toxicity to humans. The objective was to study some alternatives to break the dormancy of the buds of the rootstock vine ‘SO4’. The sprayed treatments were: T1 = water (control; T2 = hydrogen cyanamide (3%; T3 = garlic (33% and; T4 = Hydrogen Peroxide – H2O2 – (3%. The cuttings were immersed in a indole acetic acid (IAA of 5 ppm for 15 seconds and placed in plastic bags (19 cm× 5 cm× 8 cm with 50% sand + 50% commercial substrate (H. Decker® . After 04 months, were evaluated: percentage of live cuttings, aerial part height (cm, length of roots (cm and dry matter of aerial parts and root (g. Regarding the roots, root dry weight and dry matter of aerial parts, stood out the cuttings treated with H2O2 at a concentration of 3% (T4. In the present work conditions, preliminarily concluded that H2O2 at a concentration of 3% can assist in breaking dormancy of the buds of the roostock vine ‘SO4’.

  4. Proteomic analysis of embryogenesis and the acquisition of seed dormancy in Norway maple (Acer platanoides L.).

    Science.gov (United States)

    Staszak, Aleksandra Maria; Pawłowski, Tomasz Andrzej

    2014-06-17

    The proteome of zygotic embryos of Acer platanoides L. was analyzed via high-resolution 2D-SDS-PAGE and MS/MS in order to: (1) identify significant physiological processes associated with embryo development; and (2) identify changes in the proteome of the embryo associated with the acquisition of seed dormancy. Seventeen spots were identified as associated with morphogenesis at 10 to 13 weeks after flowering (WAF). Thirty-three spots were associated with maturation of the embryo at 14 to 22 WAF. The greatest changes in protein abundance occurred at 22 WAF, when seeds become fully mature. Overall, the stage of morphogenesis was characterized by changes in the abundance of proteins (tubulins and actin) associated with the growth and development of the embryo. Enzymes related to energy supply were especially elevated, most likely due to the energy demand associated with rapid growth and cell division. The stage of maturation is crucial to the establishment of seed dormancy and is associated with a higher abundance of proteins involved in genetic information processing, energy and carbon metabolism and cellular and antioxidant processes. Results indicated that a glycine-rich RNA-binding protein and proteasome proteins may be directly involved in dormancy acquisition control, and future studies are warranted to verify this association.

  5. In silico discovery of the dormancy regulons in a number of Actinobacteria genomes

    Energy Technology Data Exchange (ETDEWEB)

    Gerasimova, Anna; Dubchak, Inna; Arkin, Adam; Gelfand, Mikhail

    2010-11-16

    Mycobacterium tuberculosis is a dangerous Actinobacteria infecting nearly one third of the human population. It becomes dormant and phenotypically drug resistant in response to stresses. An important feature of the M. tuberculosis pathogenesis is the prevalence of latent infection without disease, making understanding of the mechanisms used by the bacteria to exist in this state and to switch to metabolically active infectious form a vital problem to consider. M. tuberculosis dormancy is regulated by the three-component regulatory system of two kinases (DosT and DevS) and transcriprional regulator (DevR). DevR activates transcription of a set of genes, which allow the bacteria to survive long periods of anaerobiosis, and may be important for long-term survival within the host during latent infection. The DevR-regulon is studied experimentally in M. tuberculosis and few other phylogenetically close Mycobacteria spp. As many other two-component systems, the devRS operon is autoregulated. However, the mechanism of the dormancy is not completely clear even for these bacteria and there is no data describing the dormancy regulons in other species.

  6. Seed dormancy and germination changes of snowbed species under climate warming: the role of pre- and post-dispersal temperatures

    Science.gov (United States)

    Bernareggi, Giulietta; Carbognani, Michele; Mondoni, Andrea; Petraglia, Alessandro

    2016-01-01

    Background and Aims Climate warming has major impacts on seed germination of several alpine species, hence on their regeneration capacity. Most studies have investigated the effects of warming after seed dispersal, and little is known about the effects a warmer parental environment may have on germination and dormancy of the seed progeny. Nevertheless, temperatures during seed development and maturation could alter the state of dormancy, affecting the timing of emergence and seedling survival. Here, the interplay between pre- and post-dispersal temperatures driving seed dormancy release and germination requirements of alpine plants were investigated. Methods Three plant species inhabiting alpine snowbeds were exposed to an artificial warming treatment (i.e. +1·5 K) and to natural conditions in the field. Seeds produced were exposed to six different periods of cold stratification (0, 2, 4, 8, 12 and 20 weeks at 0 °C), followed by four incubation temperatures (5, 10, 15 and 20 °C) for germination testing. Key Results A warmer parental environment produced either no or a significant increase in germination, depending on the duration of cold stratification, incubation temperatures and their interaction. In contrast, the speed of germination was less sensitive to changes in the parental environment. Moreover, the effects of warming appeared to be linked to the level of (physiological) seed dormancy, with deeper dormant species showing major changes in response to incubation temperatures and less dormant species in response to cold stratification periods. Conclusions Plants developed under warmer climates will produce seeds with changed germination responses to temperature and/or cold stratification, but the extent of these changes across species could be driven by seed dormancy traits. Transgenerational plastic adjustments of seed germination and dormancy shown here may result from increased seed viability, reduced primary and secondary dormancy state, or both, and

  7. Dormancy and germination in short-lived lepidium perfoliatu l. (brassicaceae) seeds

    International Nuclear Information System (INIS)

    Tang, An-Jun; Tian, M.; Long, Chun-Lin

    2010-01-01

    To understand germination timing in an ecological context, the response to environmental events that effect seed dormancy is central and has to be combined with knowledge of germination responses to different ecological factors. In this study, seed dormancy, germination and seedling survival of annual short-lived clasping pepper weed Lepidium perfoliatum L. (Brassicaceae) were investigated. Three types of pre-treatments viz., various temperature dry storage, light and water stress were tested as possible dormancy and survival-affecting environmental events. Fresh mature seeds were greatly dormant. Warm (30 deg. C) dry storage more facilitated breaking dormancy, they germinated well under apt conditions (e.g. 20 deg. C and 10/20 deg. C plus periodic light, 14 h/d). For those seeds which underwent after-ripening, they could germinate at a range of constant temperatures (4, 10, 15, 20, 25, and 30 deg. C) and one alternating temperature (10/20 deg. C). Under alternating temperature regimes, the final percent germination of L. perfoliatum seeds increased from 37 deg. C to 93% when temperature altered from 4/10 deg. C to 10/20 deg. C in light, then decreased with increasing temperature. The germination pattern under constant temperature conditions was similar to that under alternating temperature and significant differences in final percent germinations and rates of germination were observed among different temperatures. Under different light treatments, final germination of showed significant differences, only with 35% of germination percentage in dark, much lower than those in red and white light (i.e. 93% and 91%, respectively). GA3 could promote the germination of non-dormant seeds in dark. When water potentials were reduced, final percent germination decreased dramatically, and few seeds germinated at -0.98 MPa (generated by PEG-8000). The changes of proline content in resultant seedlings were reverse to that of final percent germination with changing water

  8. Extensive transcriptome changes during natural onset and release of vegetative bud dormancy in Populus

    Directory of Open Access Journals (Sweden)

    Glenn Thomas Howe

    2015-12-01

    Full Text Available To survive winter, many perennial plants become endodormant, a state of suspended growth maintained even in favorable growing environments. To understand vegetative bud endodormancy, we collected paradormant, endodormant, and ecodormant axillary buds from Populus trees growing under natural conditions. Of 44,441 Populus gene models analyzed using NimbleGen microarrays, we found that 1,362 (3.1% were differentially expressed among the three dormancy states, and another 429 (1.0% were differentially expressed during only one of the two dormancy transitions (false discovery rate p-value < 0.05. Of all differentially expressed genes, 69% were down-regulated from paradormancy to endodormancy, which was expected given the lower metabolic activity associated with endodormancy. Dormancy transitions were accompanied by changes in multiple genes associated with DNA methylation (via RNA-directed DNA methylation and histone modifications (via Polycomb Repressive Complex 2, confirming and extending knowledge of chromatin modification as major features of dormancy transitions. Among the chromatin-associated genes, we found two genes similar to SPT (SUPPRESSOR OF TY that were strongly up-regulated during endodormancy. Transcription factor genes and gene sets that were atypically up-regulated during endodormancy include a gene that seems to encode a trihelix transcription factor and genes associated with proteins involved in responses to ethylene, cold, and other abiotic stresses. These latter transcription factors include ETHYLENE INSENSITIVE 3 (EIN3, ETHYLENE-RESPONSIVE ELEMENT BINDING PROTEIN (EBP, ETHYLENE RESPONSE FACTOR (ERF, ZINC FINGER PROTEIN 10 (ZAT10, ZAT12, and WRKY DNA-binding domain proteins. Analyses of phytohormone-associated genes suggest important changes in responses to ethylene, auxin, and brassinosteroids occur during endodormancy. We found weaker evidence for changes in genes associated with salicylic acid and jasmonic acid, and little

  9. Effect of Time and Burial Depth on Breaking Seed dormancy and Germination of Weed Seeds

    Directory of Open Access Journals (Sweden)

    marzie mazhari

    2016-02-01

    Full Text Available Introduction: Weeds limit crop growth, development and yield through competing. Seed bank of weeds in field is one of the sources which can affect weed management and their control methods. Environmental conditions during seed maturation and following dispersal interact to influence the germination phenology of many species. Disturbance plays a key role in the maintenance of habitat for many plant species, particularly referrals, for example, fire ephemerals, desert annuals, and arable weeds. Seed germination and emergence depend on endogenous and exogenous factors. Viable seeds are dormant when all environmental conditions are appropriate for germination but seeds fail to germinate. Thus, dormancy plays an important ecological role in preventing seed germination, being a major contributor to seed persistence of some species in soil. Buried seeds of annual weeds are certainly subjected to different soil moisture conditions during their dormancy release season (winter according to the annual rainfall pattern and burial depth. Shallow buried seeds are exposed to soil moisture fluctuations that could affect their dormancy status. Laboratory studies showed that desiccation and subsequent re-hydration of seeds could stimulate germination and modify seed light requirements. Seeds buried in deeper layers of the soil would not be exposed to such fluctuations in soil moisture, but would be exposed to different soil moisture environments depending on weather and soil characteristics. The effects of interactions between temperature, and soil or seed moisture, on seed dormancy changes have been reported for several species. Therefore, the objectives of this study were to determine the effect of time and burial depth treatments on seed germination and seedling emergence of Aegilops cylindrica, Agropyrom repens, Avena fatua, Bromus dantoniae, Cynodon dactylon, Cyprus rotundus, Setaria viridis, Anthriscus sylvestris, Centurea cyanus. Materials and Methods: In

  10. The seasonal dormancy pattern and germination of Matricaria maritima subsp. inodora (L. Dostal seeds in hydrotime model terms

    Directory of Open Access Journals (Sweden)

    Anna Bochenek

    2011-01-01

    Full Text Available Changes in hydrotime model parameters were determined in Matricaria maritima L. subsp. inodora seeds during burial in a field in order to describe the seasonal dormancy pattern. Seeds were exhumed at regular intervals over a year and incubated at different water potentials at 19°C. Germination time courses were analyzed to determine hydrotime population parameters. Values of ѱb(50, ѲH and σѱb varied each month. Mean base water potential values in seeds exhumed each month were related to precipitation over 20 days before their exhumation. Soil temperature could be a trend-controlling factor of this relationship. The seeds were in deep dormancy after remaining 80-90 days in soil below or above limit temperature 15°C. The application of the hydrotime model to describe and predict seasonal dormancy patterns of weed seed is promising, especially for species with a considerable diversification of life strategies and ecophysiological flexibility of diaspores. It could also suggest mechanisms of seasonal dormancy changes of seeds in natural conditions and provide a basis for their examination. One of advantages of the dormancy pattern description of weed seeds remaining in a soil bank by means of threshold models is its simplicity.

  11. Proteome-Level Analysis of Metabolism- and Stress-Related Proteins during Seed Dormancy and Germination in Gnetum parvifolium.

    Science.gov (United States)

    Chang, Ermei; Deng, Nan; Zhang, Jin; Liu, Jianfeng; Chen, Lanzhen; Zhao, Xiulian; Abbas, M; Jiang, Zeping; Shi, Shengqing

    2018-03-21

    Gnetum parvifolium is a rich source of materials for traditional medicines, food, and oil, but little is known about the mechanism underlying its seed dormancy and germination. In this study, we analyzed the proteome-level changes in its seeds during germination using isobaric tags for relative and absolute quantitation. In total, 1,040 differentially expressed proteins were identified, and cluster analysis revealed the distinct time points during which signal transduction and oxidation-reduction activity changed. Gene Ontology analysis showed that "carbohydrate metabolic process" and "response to oxidative stress" were the main enriched terms. Proteins associated with starch degradation and antioxidant enzymes were important for dormancy-release, while proteins associated with energy metabolism and protein synthesis were up-regulated during germination. Moreover, protein-interaction networks were mainly associated with heat-shock proteins. Furthermore, in accord with changes in the energy metabolism- and antioxidant-related proteins, indole-3-acetic acid, Peroxidase, and soluble sugar content increased, and the starch content decreased in almost all six stages of dormancy and germination analyzed (S1-S6). The activity of superoxide dismutase, abscisic acid, and malondialdehyde content increased in the dormancy stages (S1-S3) and then decreased in the germination stages (S4-S6). Our results provide new insights into G. parvifolium seed dormancy and germination at the proteome and physiological levels, with implications for improving seed propagation.

  12. Respiration and hemoglobin function in the giant African bullfrog Pyxicephalus adspersus Tschudi (Anura: Pyxicephalidae) during rest, exercise and dormancy

    DEFF Research Database (Denmark)

    van Aardt, W.J; Weber, Roy E.

    2010-01-01

    The survival strategies of frogs exposed to harsh conditions include various forms of dormancy. Giant bullfrogs Pyxicephalus adspersus subjected to slow desiccation without access to moist substrata over winter in cocoons during dormancy. We found that Pyxicephalus can survive long periods of dor...

  13. Transcriptomic analysis of ‘Suli’ pear (Pyrus pyrifolia white pear group buds during the dormancy by RNA-Seq

    Directory of Open Access Journals (Sweden)

    Liu Guoqin

    2012-12-01

    Full Text Available Abstract Background Bud dormancy is a critical developmental process that allows perennial plants to survive unfavorable environmental conditions. Pear is one of the most important deciduous fruit trees in the world, but the mechanisms regulating bud dormancy in this species are unknown. Because genomic information for pear is currently unavailable, transcriptome and digital gene expression data for this species would be valuable resources to better understand the molecular and biological mechanisms regulating its bud dormancy. Results We performed de novo transcriptome assembly and digital gene expression (DGE profiling analyses of ‘Suli’ pear (Pyrus pyrifolia white pear group using the Illumina RNA-seq system. RNA-Seq generated approximately 100 M high-quality reads that were assembled into 69,393 unigenes (mean length = 853 bp, including 14,531 clusters and 34,194 singletons. A total of 51,448 (74.1% unigenes were annotated using public protein databases with a cut-off E-value above 10-5. We mainly compared gene expression levels at four time-points during bud dormancy. Between Nov. 15 and Dec. 15, Dec. 15 and Jan. 15, and Jan. 15 and Feb. 15, 1,978, 1,024, and 3,468 genes were differentially expressed, respectively. Hierarchical clustering analysis arranged 190 significantly differentially-expressed genes into seven groups. Seven genes were randomly selected to confirm their expression levels using quantitative real-time PCR. Conclusions The new transcriptomes offer comprehensive sequence and DGE profiling data for a dynamic view of transcriptomic variation during bud dormancy in pear. These data provided a basis for future studies of metabolism during bud dormancy in non-model but economically-important perennial species.

  14. A potential role for endogenous microflora in dormancy release, cytokinin metabolism and the response to fluridone in Lolium rigidum seeds.

    Science.gov (United States)

    Goggin, Danica E; Emery, R J Neil; Kurepin, Leonid V; Powles, Stephen B

    2015-02-01

    Dormancy in Lolium rigidum (annual ryegrass) seeds can be alleviated by warm stratification in the dark or by application of fluridone, an inhibitor of plant abscisic acid (ABA) biosynthesis via phytoene desaturase. However, germination and absolute ABA concentration are not particularly strongly correlated. The aim of this study was to determine if cytokinins of both plant and bacterial origin are involved in mediating dormancy status and in the response to fluridone. Seeds with normal or greatly decreased (by dry heat pre-treatment) bacterial populations were stratified in the light or dark and in the presence or absence of fluridone in order to modify their dormancy status. Germination was assessed and seed cytokinin concentration and composition were measured in embryo-containing or embryo-free seed portions. Seeds lacking bacteria were no longer able to lose dormancy in the dark unless supplied with exogenous gibberellin or fluridone. Although these seeds showed a dramatic switch from active cytokinin free bases to O-glucosylated storage forms, the concentrations of individual cytokinin species were only weakly correlated to dormancy status. However, cytokinins of apparently bacterial origin were affected by fluridone and light treatment of the seeds. It is probable that resident microflora contribute to dormancy status in L. rigidum seeds via a complex interaction between hormones of both plant and bacterial origin. This interaction needs to be taken into account in studies on endogenous seed hormones or the response of seeds to plant growth regulators. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Representing Microbial Dormancy in Soil Decomposition Models Improves Model Performance and Reveals Key Ecosystem Controls on Microbial Activity

    Science.gov (United States)

    He, Y.; Yang, J.; Zhuang, Q.; Wang, G.; Liu, Y.

    2014-12-01

    Climate feedbacks from soils can result from environmental change and subsequent responses of plant and microbial communities and nutrient cycling. Explicit consideration of microbial life history traits and strategy may be necessary to predict climate feedbacks due to microbial physiology and community changes and their associated effect on carbon cycling. In this study, we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of dormancy at six temperate forest sites with observed soil efflux ranged from 4 to 10 years across different forest types. We then extrapolated the model to all temperate forests in the Northern Hemisphere (25-50°N) to investigate spatial controls on microbial and soil C dynamics. Both models captured the observed soil heterotrophic respiration (RH), yet no-dormancy model consistently exhibited large seasonal amplitude and overestimation in microbial biomass. Spatially, the total RH from temperate forests based on dormancy model amounts to 6.88PgC/yr, and 7.99PgC/yr based on no-dormancy model. However, no-dormancy model notably overestimated the ratio of microbial biomass to SOC. Spatial correlation analysis revealed key controls of soil C:N ratio on the active proportion of microbial biomass, whereas local dormancy is primarily controlled by soil moisture and temperature, indicating scale-dependent environmental and biotic controls on microbial and SOC dynamics. These developments should provide essential support to modeling future soil carbon dynamics and enhance the avenue for collaboration between empirical soil experiment and modeling in the sense that more microbial physiological measurements are needed to better constrain and evaluate the models.

  16. Phylogeny and source climate impact seed dormancy and germination of restoration-relevant forb species.

    Science.gov (United States)

    Seglias, Alexandra E; Williams, Evelyn; Bilge, Arman; Kramer, Andrea T

    2018-01-01

    For many species and seed sources used in restoration activities, specific seed germination requirements are often unknown. Because seed dormancy and germination traits can be constrained by phylogenetic history, related species are often assumed to have similar traits. However, significant variation in these traits is also present within species as a result of adaptation to local climatic conditions. A growing number of studies have attempted to disentangle how phylogeny and climate influence seed dormancy and germination traits, but they have focused primarily on species-level effects, ignoring potential population-level variation. We examined the relationships between phylogeny, climate, and seed dormancy and germination traits for 24 populations of eight native, restoration-relevant forb species found in a wide range of climatic conditions in the Southwest United States. The seeds were exposed to eight temperature and stratification length regimes designed to mimic regional climatic conditions. Phylogenetic relatedness, overall climatic conditions, and temperature conditions at the site were all significantly correlated with final germination response, with significant among-population variation in germination response across incubation treatments for seven of our eight study species. Notably, germination during stratification was significantly predicted by precipitation seasonality and differed significantly among populations for seven species. While previous studies have not examined germination during stratification as a potential trait influencing overall germination response, our results suggest that this trait should be included in germination studies as well as seed sourcing decisions. Results of this study deepen our understanding of the relationships between source climate, species identity, and germination, leading to improved seed sourcing decisions for restorations.

  17. Garlic and H2O2 in overcoming dormancy on the vine “Cabernet Sauvignon”

    OpenAIRE

    Saavedra del Aguila Juan; Pereira Dachi Ângela; Nogueira Fernandes Elizeu; Lais Hamm Bruna; Corrêa de Almeida Fabiane; Moreira Silveira Jansen

    2015-01-01

    The objective of this experiment was to evaluate the effect of garlic extract, H2O2 and hydrogen cyanamide on dormancy break, budding and maturation of “Cabernet Sauvignon” in the Campaign Region – Brazil. In late winter 2014 and after drought pruning were performed spraying in the bud: T1 – distilled water (control); T2 – 3.0% of hydrogen cyanamide; T3 – 18.0% H2O2; and T4 – 3.0% garlic extract. It was evaluated in the field: the number of sprouted buds per plant, number of bunches per plant...

  18. Discovering genes associated with dormancy in the monogonont rotifer Brachionus plicatilis.

    Science.gov (United States)

    Denekamp, Nadav Y; Thorne, Michael A S; Clark, Melody S; Kube, Michael; Reinhardt, Richard; Lubzens, Esther

    2009-03-13

    Microscopic monogonont rotifers, including the euryhaline species Brachionus plicatilis, are typically found in water bodies where environmental factors restrict population growth to short periods lasting days or months. The survival of the population is ensured via the production of resting eggs that show a remarkable tolerance to unfavorable conditions and remain viable for decades. The aim of this study was to generate Expressed Sequence Tags (ESTs) for molecular characterisation of processes associated with the formation of resting eggs, their survival during dormancy and hatching. Four normalized and four subtractive libraries were constructed to provide a resource for rotifer transcriptomics associated with resting-egg formation, storage and hatching. A total of 47,926 sequences were assembled into 18,000 putative transcripts and analyzed using both Blast and GO annotation. About 28-55% (depending on the library) of the clones produced significant matches against the Swissprot and Trembl databases. Genes known to be associated with desiccation tolerance during dormancy in other organisms were identified in the EST libraries. These included genes associated with antioxidant activity, low molecular weight heat shock proteins and Late Embryonic Abundant (LEA) proteins. Real-time PCR confirmed that LEA transcripts, small heat-shock proteins and some antioxidant genes were upregulated in resting eggs, therefore suggesting that desiccation tolerance is a characteristic feature of resting eggs even though they do not necessarily fully desiccate during dormancy. The role of trehalose in resting-egg formation and survival remains unclear since there was no significant difference between resting-egg producing females and amictic females in the expression of the tps-1 gene. In view of the absence of vitellogenin transcripts, matches to lipoprotein lipase proteins suggest that, similar to the situation in dipterans, these proteins may serve as the yolk proteins in

  19. Discovering genes associated with dormancy in the monogonont rotifer Brachionus plicatilis

    Directory of Open Access Journals (Sweden)

    Kube Michael

    2009-03-01

    Full Text Available Abstract Background Microscopic monogonont rotifers, including the euryhaline species Brachionus plicatilis, are typically found in water bodies where environmental factors restrict population growth to short periods lasting days or months. The survival of the population is ensured via the production of resting eggs that show a remarkable tolerance to unfavorable conditions and remain viable for decades. The aim of this study was to generate Expressed Sequence Tags (ESTs for molecular characterisation of processes associated with the formation of resting eggs, their survival during dormancy and hatching. Results Four normalized and four subtractive libraries were constructed to provide a resource for rotifer transcriptomics associated with resting-egg formation, storage and hatching. A total of 47,926 sequences were assembled into 18,000 putative transcripts and analyzed using both Blast and GO annotation. About 28–55% (depending on the library of the clones produced significant matches against the Swissprot and Trembl databases. Genes known to be associated with desiccation tolerance during dormancy in other organisms were identified in the EST libraries. These included genes associated with antioxidant activity, low molecular weight heat shock proteins and Late Embryonic Abundant (LEA proteins. Real-time PCR confirmed that LEA transcripts, small heat-shock proteins and some antioxidant genes were upregulated in resting eggs, therefore suggesting that desiccation tolerance is a characteristic feature of resting eggs even though they do not necessarily fully desiccate during dormancy. The role of trehalose in resting-egg formation and survival remains unclear since there was no significant difference between resting-egg producing females and amictic females in the expression of the tps-1 gene. In view of the absence of vitellogenin transcripts, matches to lipoprotein lipase proteins suggest that, similar to the situation in dipterans, these

  20. Cell cycle arrest in plants: what distinguishes quiescence, dormancy and differentiated G1?

    Science.gov (United States)

    Velappan, Yazhini; Signorelli, Santiago; Considine, Michael J

    2017-10-17

    Quiescence is a fundamental feature of plant life, which enables plasticity, renewal and fidelity of the somatic cell line. Cellular quiescence is defined by arrest in a particular phase of the cell cycle, typically G1 or G2; however, the regulation of quiescence and proliferation can also be considered across wider scales in space and time. As such, quiescence is a defining feature of plant development and phenology, from meristematic stem cell progenitors to terminally differentiated cells, as well as dormant or suppressed seeds and buds. While the physiology of each of these states differs considerably, each is referred to as 'cell cycle arrest' or 'G1 arrest'. Here the physiology and molecular regulation of (1) meristematic quiescence, (2) dormancy and (3) terminal differentiation (cell cycle exit) are considered in order to determine whether and how the molecular decisions guiding these nuclear states are distinct. A brief overview of the canonical cell cycle regulators is provided, and the genetic and genomic, as well as physiological, evidence is considered regarding two primary questions: (1) Are the canonical cell cycle regulators superior or subordinate in the regulation of quiescence? (2) Are these three modes of quiescence governed by distinct molecular controls? Meristematic quiescence, dormancy and terminal differentiation are each predominantly characterized by G1 arrest but regulated distinctly, at a level largely superior to the canonical cell cycle. Meristematic quiescence is intrinsically linked to non-cell-autonomous regulation of meristem cell identity, and particularly through the influence of ubiquitin-dependent proteolysis, in partnership with reactive oxygen species, abscisic acid and auxin. The regulation of terminal differentiation shares analogous features with meristematic quiescence, albeit with specific activators and a greater role for cytokinin signalling. Dormancy meanwhile appears to be regulated at the level of chromatin

  1. Genetic and Physiological Characterization of Two Clusters of Quantitative Trait Loci Associated With Seed Dormancy and Plant Height in Rice

    OpenAIRE

    Ye, Heng; Beighley, Donn H.; Feng, Jiuhuan; Gu, Xing-You

    2013-01-01

    Seed dormancy and plant height have been well-studied in plant genetics, but their relatedness and shared regulatory mechanisms in natural variants remain unclear. The introgression of chromosomal segments from weedy into cultivated rice (Oryza sativa) prompted the detection of two clusters (qSD1-2/qPH1 and qSD7-2/qPH7) of quantitative trait loci both associated with seed dormancy and plant height. Together, these two clusters accounted for >96% of the variances for plant height and ~71% of t...

  2. EL ÁCIDO ABSCÍSICO ACELERA EL DESARROLLO FLORAL DE SOLIDAGO EN DÍAS CORTOS ABSCISIC ACID SPEED UP FLORAL DEVELOPMENT OF SOLIDAGO UNDER SHORT DAYS

    Directory of Open Access Journals (Sweden)

    Víctor Julio Flórez Roncancio

    2009-06-01

    Full Text Available Solidago x luteus (M. L. Greene Broulliet y Semple (= x Solidaster hybridus, x S. luteus es una planta que responde a días cortos (DC para el desarrollo floral. En este proceso se ha establecido la participación de varias fitohormonas, entre éstas, la presencia del ácido abscísico (ABA en zonas y periodos específicos durante el desarrollo de la flor lo cual sugiere su acción promotora en la velocidad de antesis floral de esta especie en DC. En este trabajo se buscaron nuevos indicios de la participación de fitohormonas presentes en la fracción ácida con el proceso de floración. En una primera etapa, extractos foliares provenientes de hojas de plantas en días largos (caracterizadas por menor velocidad de antesis floral se aplicaron en botones florales de plantas en días cortos (caracterizadas por una mayor velocidad de antesis floral. Se realizaron ocho aplicaciones con diferentes frecuencias totalizando un periodo de tratamiento de 25 días. Los resultados mostraron que las sustancias presentes en los extractos de la fracción ácida, no alteran la velocidad promedio de antesis floral en los botones florales de plantas en DC. En la segunda etapa del experimento, la cuantificación de los extractos por ELISA, permitió establecer una mayor concentración de ABA en los extractos de hojas y de botones florales de plantas en DC y de botones florales en el inicio del tratamiento. Estos resultados confirman la relación del ABA con la mayor velocidad de antesis floral en plantas de Solidago x luteus en condiciones de DC.Solidago x luteus (M.L. Greene Broulliet & Semple (= x Solidaster hybridus, x S. luteus is a plant that respond to short days (SD for flower development. In this process, there has been established the involvement of many phytohormones, between these, the presence of the abscisic acid (ABA in zones and specific periods during flower development, suggests its promoter roll on the floral anthesis period of this species under

  3. Dormancy-Associated MADS-Box (DAM) and the Abscisic Acid Pathway Regulate Pear Endodormancy Through a Feedback Mechanism.

    Science.gov (United States)

    Tuan, Pham Anh; Bai, Songling; Saito, Takanori; Ito, Akiko; Moriguchi, Takaya

    2017-08-01

    In the pear 'Kosui' (Pyrus pyrifolia Nakai), the dormancy-associated MADS-box (PpDAM1 = PpMADS13-1) gene has been reported to play an essential role in bud endodormancy. Here, we found that PpDAM1 up-regulated expression of 9-cis-epoxycarotenoid dioxygenase (PpNCED3), which is a rate-limiting gene for ABA biosynthesis. Transient assays with a dual luciferase reporter system (LUC assay) and electrophoretic mobility shift assay (EMSA) showed that PpDAM1 activated PpNCED3 expression by binding to the CArG motif in the PpNCED3 promoter. PpNCED3 expression was increased toward endodormancy release in lateral flower buds of 'Kosui', which is consistent with the induced levels of ABA, its catabolism (ABA 8'-hydroxylase) and signaling genes (type 2C protein phosphatase genes and SNF1-related protein kinase 2 genes). In addition, we found that an ABA response element (ABRE)-binding transcription factor, PpAREB1, exhibiting high expression concomitant with endodormancy release, bound to three ABRE motifs in the promoter region of PpDAM1 and negatively regulated its activity. Taken together, our results suggested a feedback regulation between PpDAM1 and the ABA metabolism and signaling pathway during endodormancy of pear. This first evidence of an interaction between a DAM and ABA biosynthesis in vitro will provide further insights into bud endodormancy regulatory mechanisms of deciduous trees including pear. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  4. Vernalization and the Chilling Requirement to Exit Bud Dormancy: Shared or Separate Regulation?

    Directory of Open Access Journals (Sweden)

    Amy M Brunner

    2014-12-01

    Full Text Available Similarities have long been recognized between vernalization, the prolonged exposure to cold temperatures that promotes the floral transition in many plants, and the chilling requirement to release bud dormancy in woody plants of temperate climates. In both cases the extended chilling period occurring during winter is used to coordinate developmental events to the appropriate seasonal time. However, whether or not these processes share common regulatory components and molecular mechanisms remain largely unknown. Both gene function and association genetics studies in Populus are beginning to answer this question. In Populus, studies have revealed that orthologs of the antagonistic flowering time genes FT and CEN/TFL1 might have central roles in both processes. We review Populus seasonal shoot development related to dormancy release and the floral transition and evidence for FT/TFL1-mediated regulation of these processes to consider the question of regulatory overlap. In addition, we discuss the potential for and challenges to integrating functional and population genomics studies to uncover the regulatory mechanisms underpinning these processes in woody plant systems.

  5. Seed dormancy alleviation of grewia tenax (forssk.): a wild fruit tree species of pakistan

    International Nuclear Information System (INIS)

    Sohail, M.; Saied, A.S.

    2015-01-01

    Grewia tenax (Forssk.) Fiori is a fruit shrub and grows wild in arid and semi-arid tropics of Asia and Africa. The species is highly valuable for the rural populations because of its edible fruit and fodder for livestock. Species has immense potential for re-vegetation of degraded lands, as it has ability to withstand soil salinity and drought. Wild stands of the species are sparse which is supposed to have some kind of seed dormancy. Seeds of G. tenax were subjected to different combinations of heat and cold seed stratification treatments in two consecutive experiments. A positive correlation (r2 = 0.97) was observed between total emergence and weeks of seed exposure to constant dry heat at 40 degree C from 0 to 4 weeks. Maximum germination (70%) was achieved, when seeds were exposed to dry heat at 40 degree C for 4 weeks as compared to control (20%). Seeds exposed to constant heat for 4 weeks also took only 4 and 5 days to reach 1st and 50% emergence, respectively as compared to untreated seeds, which took 10 and 14 days to reach 1st and 50% emergence, respectively. Moreover, emergence spread lasted only 4 days as compared to untreated seeds with 21 days. Our results indicate that seeds of G. tenax possess a limited physiological dormancy which can be overcome by heat stratification. (author)

  6. METHODS FOR OVERCOMING SEED DORMANCY AND THE INITIAL GROWTH OF Ziziphus joazeiro Mart. IN DIFFERENT SOILS

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    JOSENARA DAIANE DE SOUZA COSTA

    2016-01-01

    Full Text Available Considering the potential and importance of biodiversity of the Caatinga biome, studies on endemic species are relevant to conservation of its natural resources. The objectives of this work was to evaluate seed viability and physical methods for overcoming seed dormancy in juazeiro (Ziziphus joazeiro Mart. and assess the influence of different types of soil on the initial growth of juazeiro plants. The experiments were conducted in three stages. In the first stage, the viability of seeds from different lots was evaluated using the tetrazolium test. The second stage was conducted in a plant nursery, evaluating the application of physical processes (scarification with sandpaper and hammer in overcoming seed dormancy, and the initial growth of the plants. In the third step, the chlorophyll a and b contents, gas exchange and dry matter accumulation were evaluated in young juazeiro plants in three types of soil (Oxisol, Entisol and Vertisol. The results indicate that the viability of juazeiro seeds is greatly influenced by differences between the progenitor plants and by storage conditions, which enable a longevity of two years when stored at 22°C and 16% of relative humidity. The scarification methods with sandpaper and hammer are not efficient to reduce the time and uniform seed germination. The juazeiro plants have high growth potential in different edaphic environments, adapting well to soils of different textures and chemical compositions.

  7. Effect of storage in overcoming seed dormancy of Annona coriacea Mart. seeds

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    DAIANE M. DRESCH

    2014-12-01

    Full Text Available The aim of this study was to evaluate the effect of pre-treatments on overcoming dormancy of A. coriacea seeds. Seeds were processed and stored in polyethylene bags at temperatures of at -18°C (42% RH, 5°C (34% RH, 15°C (60% RH and 25°C (34% RH, during 0, 30, 60, 90, 120 and 150 days. After storage, seeds were immersed in 350 mg.L−1 gibberellic acid for 144 hours. Sowing was carried out in plastic bags containing Red Latosol + Bioplant®. Moisture content, emergence percentage, emergence speed index, length and dry mass of seedlings, were evaluated. The experimental design was completely randomized in a factorial with four replications of 50 seeds each. The seed storage at 5°C and subsequent immersion in gibberellic acid was efficient to reach high percentage, emergence speed and plant growth. A. coriacea seeds showed non-deep simple morphophysiological dormancy wherein the physiological component can be overcome after the seeds are storage at 5°C for a maximum period of 53 days and subsequent immersed in exogenous GA (350 mg.L−1 for 144 hours.

  8. Effect of storage in overcoming seed dormancy of Annona coriacea Mart. seeds.

    Science.gov (United States)

    Dresch, Daiane M; Scalon, Silvana P Q; Masetto, Tathiana E

    2014-12-01

    The aim of this study was to evaluate the effect of pre-treatments on overcoming dormancy of A. coriacea seeds. Seeds were processed and stored in polyethylene bags at temperatures of at -18°C (42% RH), 5°C (34% RH), 15°C (60% RH) and 25°C (34% RH), during 0, 30, 60, 90, 120 and 150 days. After storage, seeds were immersed in 350 mg.L-1 gibberellic acid for 144 hours. Sowing was carried out in plastic bags containing Red Latosol + Bioplant®. Moisture content, emergence percentage, emergence speed index, length and dry mass of seedlings, were evaluated. The experimental design was completely randomized in a factorial with four replications of 50 seeds each. The seed storage at 5°C and subsequent immersion in gibberellic acid was efficient to reach high percentage, emergence speed and plant growth. A. coriacea seeds showed non-deep simple morphophysiological dormancy wherein the physiological component can be overcome after the seeds are storage at 5°C for a maximum period of 53 days and subsequent immersed in exogenous GA (350 mg.L-1 for 144 hours).

  9. Live to cheat another day: bacterial dormancy facilitates the social exploitation of β-lactamases.

    Science.gov (United States)

    Medaney, Frances; Dimitriu, Tatiana; Ellis, Richard J; Raymond, Ben

    2016-03-01

    The breakdown of antibiotics by β-lactamases may be cooperative, since resistant cells can detoxify their environment and facilitate the growth of susceptible neighbours. However, previous studies of this phenomenon have used artificial bacterial vectors or engineered bacteria to increase the secretion of β-lactamases from cells. Here, we investigated whether a broad-spectrum β-lactamase gene carried by a naturally occurring plasmid (pCT) is cooperative under a range of conditions. In ordinary batch culture on solid media, there was little or no evidence that resistant bacteria could protect susceptible cells from ampicillin, although resistant colonies could locally detoxify this growth medium. However, when susceptible cells were inoculated at high densities, late-appearing phenotypically susceptible bacteria grew in the vicinity of resistant colonies. We infer that persisters, cells that have survived antibiotics by undergoing a period of dormancy, founded these satellite colonies. The number of persister colonies was positively correlated with the density of resistant colonies and increased as antibiotic concentrations decreased. We argue that detoxification can be cooperative under a limited range of conditions: if the toxins are bacteriostatic rather than bacteridical; or if susceptible cells invade communities after resistant bacteria; or if dormancy allows susceptible cells to avoid bactericides. Resistance and tolerance were previously thought to be independent solutions for surviving antibiotics. Here, we show that these are interacting strategies: the presence of bacteria adopting one solution can have substantial effects on the fitness of their neighbours.

  10. Seed dormancy and germination of Halophila ovalis mediated by simulated seasonal temperature changes

    Science.gov (United States)

    Statton, John; Sellers, Robert; Dixon, Kingsley W.; Kilminster, Kieryn; Merritt, David J.; Kendrick, Gary A.

    2017-11-01

    The seagrass, Halophila ovalis plays an important ecological and sediment stability role in estuarine systems in Australia with the species in decline in many sites. Halophila ovalis is a facultative annual, relying mainly on recruitment from the sediment seed bank for the annual regeneration of meadows. Despite this, there is little understanding of seed dormancy releasing mechanisms and germination cues. Using H. ovalis seed from the warm temperate Swan River Estuary in Western Australia, the germination ecology of H. ovalis was investigated by simulating the natural seasonal variation in water temperatures. The proportion of germinating seeds was found to be significantly different among temperature treatments (p < 0.001). The treatment with the longest period of cold exposure at 15 °C followed by an increase in temperature to 20-25 °C (i.e. cold stratification) had the highest final mean germination of 32% and the fastest germination rate. Seeds exposed to constant mean winter temperatures of 15 °C had the slowest germination rate with less than two seeds germinating over 118 days. Thus temperature is a key germination cue for H. ovalis seeds and these data infer that cold stratification is an important dormancy releasing mechanism. This finding has implications for recruitment in facultative annual species like H. ovalis under global warming since the trend for increasing water temperatures in the region may limit seed-based recruitment in the future.

  11. Gas exchange and ventilation during dormancy in the tegu lizard tupinambis merianae

    Science.gov (United States)

    de Andrade DV; Abe

    1999-12-01

    The tegu lizard Tupinambis merianae exhibits an episodic ventilatory pattern when dormant at 17 degrees C but a uniform ventilatory pattern when dormant at 25 degrees C. At 17 degrees C, ventilatory episodes were composed of 1-22 breaths interspaced by non-ventilatory periods lasting 1.8-26 min. Dormancy at the higher body temperature was accompanied by higher rates of O(2) consumption and ventilation. The increase in ventilation was due only to increases in breathing frequency with no change observed in tidal volume. The air convection requirement for O(2) did not differ at the two body temperatures. The respiratory quotient was 0.8 at 17 degrees C and 1.0 at 25 degrees C. We found no consistent relationship between expired gas composition and the start/end of the ventilatory period during episodic breathing at 17 degrees C. However, following non-ventilatory periods of increasing duration, there was an increase in the pulmonary O(2) extraction that was not coupled to an equivalent increase in elimination of CO(2) from the lungs. None of the changes in the variables studied could alone explain the initiation/termination of episodic ventilation in the tegus, suggesting that breathing episodes are shaped by a complex interaction between many variables. The estimated oxidative cost of breathing in dormant tegus at 17 degrees C was equivalent to 52.3 % of the total metabolic rate, indicating that breathing is the most costly activity during dormancy.

  12. Interacting effects of genetic variation for seed dormancy and flowering time on phenology, life history, and fitness of experimental Arabidopsis thaliana populations over multiple generations in the field.

    Science.gov (United States)

    Taylor, Mark A; Cooper, Martha D; Sellamuthu, Reena; Braun, Peter; Migneault, Andrew; Browning, Alyssa; Perry, Emily; Schmitt, Johanna

    2017-10-01

    Major alleles for seed dormancy and flowering time are well studied, and can interact to influence seasonal timing and fitness within generations. However, little is known about how this interaction controls phenology, life history, and population fitness across multiple generations in natural seasonal environments. To examine how seed dormancy and flowering time shape annual plant life cycles over multiple generations, we established naturally dispersing populations of recombinant inbred lines of Arabidopsis thaliana segregating early and late alleles for seed dormancy and flowering time in a field experiment. We recorded seasonal phenology and fitness of each genotype over 2 yr and several generations. Strong seed dormancy suppressed mid-summer germination in both early- and late-flowering genetic backgrounds. Strong dormancy and late-flowering genotypes were both necessary to confer a winter annual life history; other genotypes were rapid-cycling. Strong dormancy increased within-season fecundity in an early-flowering background, but decreased it in a late-flowering background. However, there were no detectable differences among genotypes in population growth rates. Seasonal phenology, life history, and cohort fitness over multiple generations depend strongly upon interacting genetic variation for dormancy and flowering. However, similar population growth rates across generations suggest that different life cycle genotypes can coexist in natural populations. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  13. After-ripening induced transcriptional changes of hormonal genes in wheat seeds: the cases of brassinosteroids, ethylene, cytokinin and salicylic acid.

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    Vijaya R Chitnis

    Full Text Available Maintenance and release of seed dormancy is regulated by plant hormones; their levels and seed sensitivity being the critical factors. This study reports transcriptional regulation of brassinosteroids (BR, ethylene (ET, cytokinin (CK and salicylic acid (SA related wheat genes by after-ripening, a period of dry storage that decays dormancy. Changes in the expression of hormonal genes due to seed after-ripening did not occur in the anhydrobiotic state but rather in the hydrated state. After-ripening induced dormancy decay appears to be associated with imbibition mediated increase in the synthesis and signalling of BR, via transcriptional activation of de-etiolated2, dwarf4 and brassinosteroid signaling kinase, and repression of brassinosteroid insensitive 2. Our analysis is also suggestive of the significance of increased ET production, as reflected by enhanced transcription of 1-aminocyclopropane-1-carboxylic acid oxidase in after-ripened seeds, and tight regulation of seed response to ET in regulating dormancy decay. Differential transcriptions of lonely guy, zeatin O-glucosyltransferases and cytokinin oxidases, and pseudo-response regulator between dormant and after-ripened seeds implicate CK in the regulation of seed dormancy in wheat. Our analysis also reflects the association of dormancy decay in wheat with seed SA level and NPR independent SA signaling that appear to be regulated transcriptionally by phenylalanine ammonia lyase, and whirly and suppressor of npr1 inducible1 genes, respectively. Co-expression clustering of the hormonal genes implies the significance of synergistic and antagonistic interaction between the different plant hormones in regulating wheat seed dormancy. These results contribute to further our understanding of the molecular features controlling seed dormancy in wheat.

  14. Interaction between seed dormancy-release mechanism, environment and seed bank strategy for a widely distributed perennial legume, Parkinsonia aculeata (Caesalpinaceae).

    Science.gov (United States)

    Van Klinken, Rieks D; Lukitsch, Bert; Cook, Carly

    2008-08-01

    Parkinsonia aculeata (Caesalpinaceae) is a perennial legume with seeds that have hard-seeded (physical) dormancy and are potentially very long-lived. Seed dormancy is a characteristic that can both help maximize the probability of seedling establishment and spread the risk of recruitment failure across years (bet-hedging). In this study, dormancy-release patterns are described across the diverse environments in which this species occurs in order to test whether wet heat (incubation under wet, warm-to-hot, conditions) alone can explain those patterns, and in order to determine the likely ecological role of physical dormancy across this species distribution. A seed burial trial was conducted across the full environmental distribution of P. aculeata in Australia (arid to wet-dry tropics, uplands to wetlands, soil surface to 10 cm deep). Wet heat explained the pattern of dormancy release across all environments. Most seeds stored in the laboratory remained dormant throughout the trial (at least 84 %). Dormancy release was quickest for seeds buried during the wet season at relatively high rainfall, upland sites (only 3 % of seeds remained dormant after 35 d). The longest-lived seeds were in wetlands (9 % remained dormant after almost 4 years) and on the soil surface (57 % after 2 years). There was no consistent correlation between increased aridity and rate of dormancy release. The results suggest that physical dormancy in P. aculeata is a mechanism for maximizing seedling establishment rather than a bet-hedging strategy. However, seed persistence can occur in environmental refuges where dormancy-release cues are weak and conditions for germination and establishment are poor (e.g. under dense vegetation or in more arid micro-environments) or unsuitable (e.g. when seeds are inundated or on the soil surface). Risks of recruitment failure in suboptimal environments could therefore be reduced by inter-year fluctuations in microclimate or seed movement.

  15. Overexpression of a peach cbf-transcription factor gene in apple regulates both dormancy and freezing tolerance in apple

    Science.gov (United States)

    Economic production of fruit trees in a temperate climate is dependent upon seasonal changes in cold acclimation and dormancy. Evidence indicates that these processes will be greatly affected by climate change (higher atmospheric carbon dioxide and temperatures). This problem may also be exacerbat...

  16. Tumour cell dormancy as a contributor to the reduced survival of GBM patients who received standard therapy.

    Science.gov (United States)

    Tong, Luqing; Yi, Li; Liu, Peidong; Abeysekera, Iruni Roshanie; Hai, Long; Li, Tao; Tao, Zhennan; Ma, Haiwen; Xie, Yang; Huang, Yubao; Yu, Shengping; Li, Jiabo; Yuan, Feng; Yang, Xuejun

    2018-07-01

    Glioblastoma multiforme (GBM) is a fatal cancer with varying life expectancy, even for patients undergoing the same standard therapy. Identification of differentially expressed genes in GBM patients with different survival rates may benefit the development of effective therapeutic strategies. In the present study, key pathways and genes correlated with survival in GBM patients were screened with bioinformatic analysis. Included in the study were 136 eligible patients who had undertaken surgical resection of GBM followed by temozolomide (TMZ) chemoradiation and long-term therapy with TMZ. A total of 383 differentially expressed genes (DEGs) related to GBM survival were identified. Gene Ontology and pathway enrichment analysis as well as hub gene screening and module analysis were performed. As expected, angiogenesis and migration of GBM cells were closely correlated with a poor prognosis. Importantly, the results also indicated that cell dormancy was an essential contributor to the reduced survival of GBM patients. Given the lack of specific targeted genes and pathways known to be involved in tumour cell dormancy, we proposed enriched candidate genes related to the negative regulation of cell proliferation, signalling pathways regulating pluripotency of stem cells and neuroactive ligand-receptor interaction, and 3 hub genes (FTH1, GRM1 and DDIT3). Maintaining persistent cell dormancy or preventing tumour cells from entering dormancy during chemoradiation should be a promising therapeutic strategy.

  17. Predicting seed dormancy loss and germination timing for Bromus tectorum in a semi-arid environment using hydrothermal time models

    Science.gov (United States)

    Susan E. Meyer; Phil S. Allen

    2009-01-01

    A principal goal of seed germination modelling for wild species is to predict germination timing under fluctuating field conditions. We coupled our previously developed hydrothermal time, thermal and hydrothermal afterripening time, and hydration-dehydration models for dormancy loss and germination with field seed zone temperature and water potential measurements from...

  18. Global biogeography of seed dormancy is determined by seasonality and seed size: a case study in the legumes.

    Science.gov (United States)

    Rubio de Casas, Rafael; Willis, Charles G; Pearse, William D; Baskin, Carol C; Baskin, Jerry M; Cavender-Bares, Jeannine

    2017-06-01

    Seed dormancy is expected to provide ecological advantages by adjusting germination to the favorable growth period. However, many species produce nondormant seeds, particularly in wet tropical forests, a biogeographic pattern that is not well accounted for in current models. We hypothesized that the global distribution of dormant seeds derives from their adaptive value in predictably fluctuating (i.e. seasonal) environments. However, the advantage conferred by dormancy might ultimately depend on other seed attributes, particularly size. This general model was tested within a phylogenetically informed framework using a data set comprising > 216 000 world-wide observations of Fabaceae, spanning three orders of magnitude in seed size and including both dormant and nondormant seeds. Our results confirmed our hypothesis: nondormant seeds can only evolve in climates with long growing seasons and/or in lineages that produce larger seeds. Conversely, dormancy should be evolutionarily stable in temperate lineages with small seeds. When the favorable season is fleeting, seed dormancy is the only adaptive strategy. Based on these results, we predict that, within a given lineage, taxa producing larger, nondormant seeds will necessarily predominate in aseasonal environments, while plants bearing small, dormant seeds will be dominant under short growing seasons. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  19. 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

  20. Germination and dormancy of single tomato seeds : a study using non-invasive molecular and biophysical techniques

    NARCIS (Netherlands)

    Spoelstra, P.

    2002-01-01

    Formation , germination and dormancy of seeds are important steps in the life cycle of higher plants. The seed is the generative dispersal unit, which enables plants to spread and survive through periods or seasons of less favourable conditions. In agriculture tomato is

  1. Evolutionary diversification of galactinol synthases in Rosaceae: adaptive roles of galactinol and raffinose during apple bud dormancy.

    Science.gov (United States)

    Falavigna, Vítor da Silveira; Porto, Diogo Denardi; Miotto, Yohanna Evelyn; Santos, Henrique Pessoa Dos; Oliveira, Paulo Ricardo Dias de; Margis-Pinheiro, Márcia; Pasquali, Giancarlo; Revers, Luís Fernando

    2018-01-24

    Galactinol synthase (GolS) is a key enzyme in the biosynthetic pathway of raffinose family oligosaccharides (RFOs), which play roles in carbon storage, signal transduction, and osmoprotection. The present work assessed the evolutionary history of GolS genes across the Rosaceae using several bioinformatic tools. Apple (Malus × domestica) GolS genes were transcriptionally characterized during bud dormancy, in parallel with galactinol and raffinose measurements. Additionally, MdGolS2, a candidate to regulate seasonal galactinol and RFO content during apple bud dormancy, was functionally characterized in Arabidopsis. Evolutionary analyses revealed that whole genome duplications have driven GolS gene evolution and diversification in Rosaceae speciation. The strong purifying selection identified in duplicated GolS genes suggests that differential gene expression might define gene function better than protein structure. Interestingly, MdGolS2 was differentially expressed during bud dormancy, concomitantly with the highest galactinol and raffinose levels. One of the intrinsic adaptive features of bud dormancy is limited availability of free water; therefore, we generated transgenic Arabidopsis plants expressing MdGolS2. They showed higher galactinol and raffinose contents and increased tolerance to water deficit. Our results suggest that MdGolS2 is the major GolS responsible for RFO accumulation during apple dormancy, and these carbohydrates help to protect dormant buds against limited water supply. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. Seed Dormancy, After‐ripening and Light Requirements of Four Annual Asteraceae in South‐western Australia

    Science.gov (United States)

    SCHÜTZ, W.; MILBERG, P.; LAMONT, B. B.

    2002-01-01

    The role of dormancy, temperature and light in the regulation of seed germination of four annual Asteraceae from south‐western Australia was investigated. The experiments aimed to identify after‐ripening patterns, and to relate these to climatic conditions of the habitat in which the species occur. Seeds of all species were strongly dormant at maturity and maintained high levels of dormancy for time periods corresponding to the duration of summer in south‐western Australia. Dry after‐ripening was promoted best by temperatures lower than those prevailing in the dry season, although differences among storage temperatures were mostly insignificant. Germination percentages were highest at average winter temperatures (15 °C). A logistic model revealed significant differences in germinability among species, but not between incubation temperatures or light and dark treatments across species. Three species with seeds >0·5 mg germinated better in darkness than in light, whereas germination in darkness was almost inhibited in the species with the smallest seeds (0·14 mg). The course of dormancy loss, tested over a range of fluctuating incubation temperatures (7–30 °C), showed that seeds of three species came out of dormancy first at temperatures that prevail in south‐western Australia during the winter (10–15 °C). Seeds from one species, introduced from South Africa, first lost dormancy at the lowest temperature (7 °C). All species showed after‐ripening patterns of Type 1, typical of species growing in Mediterranean climates. The germination characteristics of the investigated species can be interpreted as ensuring that initial growth and establishment occur during the winter growing season, thereby avoiding the hot and dry summer conditions that follow seed dispersal. PMID:12451026

  3. Analysis of the embryo proteome of sycamore (Acer pseudoplatanus L.) seeds reveals a distinct class of proteins regulating dormancy release.

    Science.gov (United States)

    Pawłowski, Tomasz Andrzej; Staszak, Aleksandra Maria

    2016-05-20

    Acer pseudoplatanus seeds are characterized by a deep physiological embryo dormancy that requires a few weeks of cold stratification in order to promote germination. Understanding the function of proteins and their related metabolic pathways, in conjunction with the plant hormones implicated in the breaking of seed dormancy, would expand our knowledge pertaining to this process. In this study, a proteomic approach was used to analyze the changes occurring in seeds in response to cold stratification, which leads to dormancy release. In addition, the involvement of abscisic (ABA) and gibberellic acids (GA) was also examined. Fifty-three proteins showing significant changes were identified by mass spectrometry. An effect of ABA on protein variation was observed at the beginning of stratification, while the influence of GA on protein abundance was observed during the middle phase of stratification. The majority of proteins associated with dormancy breaking in the presence of only water, and also ABA or GA, were classified as being involved in metabolism and genetic information processing. For metabolic-related proteins, the effect of ABA on protein abundance was stimulatory for half of the proteins and inhibitory for half of the proteins. On the other hand, the effect on genetic information processing related proteins was stimulatory. GA was found to upregulate both metabolic-related and genetic information processing-related proteins. While seed dormancy breaking depends on proteins involved in a variety of processes, proteins associated with methionine metabolism (adenosine kinase, methionine synthase) and glycine-rich RNA binding proteins appear to be of particular importance. Copyright © 2016 Elsevier GmbH. All rights reserved.

  4. Dormancy-breaking requirements of Sophora tomentosa and Erythrina speciosa (Fabaceae seeds

    Directory of Open Access Journals (Sweden)

    Carolina Maria Luzia Delgado

    2015-03-01

    Full Text Available The physical dormancy of seeds has been poorly studied in species from tropical forests, such as the Atlantic Forest. This study aimed to examine the effect of moderate alternating temperatures on breaking the physical dormancy of seeds, the morphoanatomy and histochemistry of seed coats, and to locate the structure/region responsible for water entrance into the seed, after breaking the physical dormancy of seeds of two woody Fabaceae (subfamily Faboideae species that occur in the Brazilian Atlantic Forest: Sophora tomentosa and Erythrina speciosa. To assess temperature effect, seeds were incubated in several temperature values that occur in the Atlantic Forest. For morphological and histochemical studies, sections of fixed seeds were subjected to different reagents, and were observed using light or epifluorescence microscopy, to analyze the anatomy and histochemistry of the seed coat. Treated and non-treated seeds were also analyzed using a scanning electron microscope (SEM to observe the morphology of the seed coat. To localize the specific site of water entrance, the seeds were blocked with glue in different regions and also immersed in ink. In the present work a maximum temperature fluctuation of 15ºC was applied during a period of 20 days and these conditions did not increase the germination of S. tomentosa or E. speciosa. These results may indicate that these seeds require larger fluctuation of temperature than the applied or/and longer period of exposition to the temperature fluctuation. Blocking experiments water inlet combined with SEM analysis of the structures of seed coat for both species showed that besides the lens, the hilum and micropyle are involved in water absorption in seeds scarified with hot water. In seeds of E. speciosa the immersion of scarified seeds into an aniline aqueous solution showed that the solution first entered the seed through the hilum. Both species showed seed morphological and anatomical features for seed

  5. Gene expression analysis by cDNA-AFLP highlights a set of new signaling networks and translational control during seed dormancy breaking in Nicotiana plumbaginifolia.

    Science.gov (United States)

    Bove, Jérôme; Lucas, Philippe; Godin, Béatrice; Ogé, Laurent; Jullien, Marc; Grappin, Philippe

    2005-03-01

    Seed dormancy in Nicotiana plumbaginifolia is characterized by an abscisic acid accumulation linked to a pronounced germination delay. Dormancy can be released by 1 year after-ripening treatment. Using a cDNA-amplified fragment length polymorphism (cDNA-AFLP) approach we compared the gene expression patterns of dormant and after-ripened seeds, air-dry or during one day imbibition and analyzed 15,000 cDNA fragments. Among them 1020 were found to be differentially regulated by dormancy. Of 412 sequenced cDNA fragments, 83 were assigned to a known function by search similarities to public databases. The functional categories of the identified dormancy maintenance and breaking responsive genes, give evidence that after-ripening turns in the air-dry seed to a new developmental program that modulates, at the RNA level, components of translational control, signaling networks, transcriptional control and regulated proteolysis.

  6. Cypripedium calceolus germination in situ: seed longevity, and dormancy breakage by long incubation and cold winters

    Directory of Open Access Journals (Sweden)

    Hanne N. Rasmussen

    2012-02-01

    Full Text Available A successful in situ germination experiment with Cypripedium calceolus, the European Lady’s slipper, is reported here for the first time. The seeds originated from controlled pollinations within and between two closely related Danish populations. The seeds were sown ripe in seed packets in proximity of mother plants. Germination was first observed after 4.5 y in the ground, following two successive cold and snowy winters, and only in one population. Seedlings expanded through the sides of the broken testa and were hair-less. A corresponding set of seeds, germinated in vitro as asymbiotic controls, responded positively to repeated cold stratifications after long incubation, suggesting that time (leaching? and chilling are dormancy breakage factors.

  7. Yields of alfalfa varieties with different fall dormancy levels in northeast china

    International Nuclear Information System (INIS)

    Chen, J.S.; Zhu, R.F.; Di, G.L.

    2014-01-01

    Fall dormancy (FD) is an important indicator of winter hardiness in alfalfa (Medicago sativa L.), the relationship between FD and the yield potential of alfalfa varieties were investigated to survey annual dry matter (DM) yields with FD levels in the northeast regions with cold winters. During three consecutive years, all varieties of five FD levels survived over the winter without any persistency problems and there were no differences in annual DM yields of varieties among FD levels. Among the same FD varieties, DM yields for some of the dormant, semi-dormant and non-dormant varieties were found no correlated with FD levels. In conclusion, it suggests that different FD levels no effected on yields of alfalfa in the cold regions, such as North-east China. (author)

  8. Dormancy overcoming, temperatures and substrates on germination of Mimosa tenuiflora Willd seeds

    Directory of Open Access Journals (Sweden)

    Clarisse Pereira Benedito

    2017-03-01

    Full Text Available Mimosa tenuiflora Willd., popularly known as jurema-preta, is an arboreal species of great importance for the brazilian Northeast due to its uses as a medicinal plant and in the restoration of degraded soils. No information is available in the Rules for Seed Analysis and the Instructions for Seed Analysis of Forest Species regarding ideal conditions for of this species. Thus, this study aimed at evaluating the influence of pre-germination treatments, in addition to verifying the germination performance at different temperatures and in different substrates. In both experiments, four replicates of 25 seeds were used for each treatment. In experiment I, seeds were submitted to the following methods for overcoming dormancy: witness - Intact seeds (T1 immersion in water at 100 °C for 1 (T2, 2 (T3, 3 (T4, 4 (T5, 5 (T6 and 6 min (T7, immersion in concentrated sulfuric acid for 1 (T8, 4 (T9, 7 (T10, 10 (T11 and 13 min (T12, scarification on sandpaper n° 80 (T13 and lopping in the region opposite the micropyle (T14. In experiment II, seed germination was evaluated in four types of substrates: between sand, paper on, paper roll and between vermiculite and at six different temperatures: 20, 25, 30, 35, 40 °C and alternating between 20 and 30 °C. Immersion in hot water for 1, 2, 3, 4, 5 and 6 min, sulfuric acid treatment for 10 and 13 min, sand paper and lopping were the most appropriate treatments to overcome seed dormancy. The seed germination of M. Tenuiflora should be carried out at 25 °C on paper roll substrate.

  9. Research on Overcoming the Dormancy Problem of Molekhia (Corchorus olitorius L. Seeds

    Directory of Open Access Journals (Sweden)

    Burcu TUNCER

    2017-10-01

    Full Text Available In this study, the effect of different seed applications on germination and emergence in order to break dormancy of the seeds of molekhia (Corchorus olitorius L. which is used as fiber, medicinal plant and consumed as a vegetable, was investigated. For this purpose, sterilized seeds were exposed to boiling water (95 ºC; 10 and 30 seconds, 1, 5 and 10 minutes, hot water (80 ºC; 5, 10, 15 and 20 minutes, sulfuric acid (98%; 5, 10, 15, 20, 25 and 30 minutes and pre-cooling (4 ºC; 2, 3 and 4 days treatments. The experiments were carried out according to randomized blocks trial design with 4 replications and 50 seeds per replicate. According to results obtained, germination rate 0.00-97.00%, average germination time 0.00-3.98 days, germination index 0.00-46.89, emergence rate 0.00-82.00%, average emergence time 0.00-7.52 days, emergence index 0.00-18.70, hypocotyl length 0.00-1.79 cm and radicle length values varied between 0.00 and 4.28 cm. The most successful treatments in terms of germination and emergence parameters were pre-chilling, sulfuric acid (for 5 and 10 minutes and boiled water (at 95 ºC for 10 seconds applications. As a result of the study, in order to remove the dormancy from the Corchorus olitorius L. seeds, treatment of the seeds with pre-cooling (4 ºC for 2 days in a humid environment before sowing would be easily practiced.

  10. Defining the role of fire in alleviating seed dormancy in a rare Mediterranean endemic subshrub.

    Science.gov (United States)

    Cross, Adam T; Paniw, Maria; Ojeda, Fernando; Turner, Shane R; Dixon, Kingsley W; Merritt, David J

    2017-09-01

    Fire is a topical issue in the management of many ecosystems globally that face a drying climate. Understanding the role of fire in such ecosystems is critical to inform appropriate management practices, particularly in the case of rare and ecologically specialized species. The Mediterranean heathlands are highly fire-prone and occur in a biodiversity hotspot increasingly threatened by human activities, and determining the reproductive thresholds of at-risk heathland species is critical to ensuring the success of future conservation initiatives. This study examined the germination biology of the threatened carnivorous subshrub Drosophyllum lusitanicum , with specific focus on the role of fire-related cues (heat and smoke) in combination with seasonal temperatures and moisture conditions to determine how these factors regulate seed dormancy and germination. We found that D. lusitanicum produces water-permeable, physiologically dormant seeds with a fully developed, capitate embryo that when fresh (~1 month old) and without treatment germinate to 20-40 % within 4-8 weeks. Seeds possess a restricted thermal window (15-20 °C) for germination and a neutral photoblastic response. Seed dormancy was overcome through precision nicking of the seed coat (>90 % germination) or by short exposure to dry heat (80 or 100 °C) for 5-30 min (60-100 % germination). We propose seedling emergence from the soil seed bank may be cued by the passage of fire, or by soil disturbance from the movement and browsing of animals. Long-term population viability is likely to be contingent upon appropriate management of the persistent soil seed bank, as well as the adequate management of key ecological disturbances such as fire. Drosophyllum lusitanicum faces an increasingly bleak future in the absence of conservation and management initiatives aimed at reducing habitat fragmentation in heathlands and aligning fire management and livestock practices with biodiversity outcomes.

  11. In vitro binding of Sorghum bicolor transcription factors ABI4 and ABI5 to a conserved region of a GA 2-OXIDASE promoter: possible role of this interaction in the expression of seed dormancy

    OpenAIRE

    Cantoro, Renata; Crocco, Carlos Daniel; Benech-Arnold, Roberto Luis; Rodr?guez, Mar?a Ver?nica

    2013-01-01

    The precise adjustment of the timing of dormancy release according to final grain usage is still a challenge for many cereal crops. Grain sorghum [Sorghum bicolor (L.) Moench] shows wide intraspecific variability in dormancy level and susceptibility to pre-harvest sprouting (PHS). Both embryo sensitivity to abscisic acid (ABA) and gibberellin (GA) metabolism play an important role in the expression of dormancy of the developing sorghum grain. In previous works, it was shown that, simultaneous...

  12. OeFAD8, OeLIP and OeOSM expression and activity in cold-acclimation of Olea europaea, a perennial dicot without winter-dormancy.

    Science.gov (United States)

    D'Angeli, Simone; Matteucci, Maya; Fattorini, Laura; Gismondi, Angelo; Ludovici, Matteo; Canini, Antonella; Altamura, Maria Maddalena

    2016-05-01

    Cold-acclimation genes in woody dicots without winter-dormancy, e.g., olive-tree, need investigation. Positive relationships between OeFAD8, OeOSM , and OeLIP19 and olive-tree cold-acclimation exist, and couple with increased lipid unsaturation and cutinisation. Olive-tree is a woody species with no winter-dormancy and low frost-tolerance. However, cold-tolerant genotypes were empirically selected, highlighting that cold-acclimation might be acquired. Proteins needed for olive-tree cold-acclimation are unknown, even if roles for osmotin (OeOSM) as leaf cryoprotectant, and seed lipid-transfer protein for endosperm cutinisation under cold, were demonstrated. In other species, FAD8, coding a desaturase producing α-linolenic acid, is activated by temperature-lowering, concomitantly with bZIP-LIP19 genes. The research was focussed on finding OeLIP19 gene(s) in olive-tree genome, and analyze it/their expression, and that of OeFAD8 and OeOSM, in drupes and leaves under different cold-conditions/developmental stages/genotypes, in comparison with changes in unsaturated lipids and cell wall cutinisation. Cold-induced cytosolic calcium transients always occurred in leaves/drupes of some genotypes, e.g., Moraiolo, but ceased in others, e.g., Canino, at specific drupe stages/cold-treatments, suggesting cold-acclimation acquisition only in the latter genotypes. Canino and Moraiolo were selected for further analyses. Cold-acclimation in Canino was confirmed by an electrolyte leakage from leaf/drupe membranes highly reduced in comparison with Moraiolo. Strong increases in fruit-epicarp/leaf-epidermis cutinisation characterized cold-acclimated Canino, and positively coupled with OeOSM expression, and immunolocalization of the coded protein. OeFAD8 expression increased with cold-acclimation, as the production of α-linolenic acid, and related compounds. An OeLIP19 gene was isolated. Its levels changed with a trend similar to OeFAD8. All together, results sustain a positive

  13. Breaking of Dormancy of Erythrina crista-galli Seeds Quebra de Dormência de Sementes de Erythrina crista-galli

    Directory of Open Access Journals (Sweden)

    Ariadne Josiane Castoldi Silva

    2011-03-01

    Full Text Available

    Erythrina crista-galli L., Fabaceae, a medium-sized N-fixing tree, is native to flooding soils of several Brazilian biomes. Its cultivation has interest for ornamental and ecological restoration purposes. Information on seed coat dormancy is conflicting and inexact, therefore the present work aimed to verify it and to define methods for its overcoming. The study was composed by two experiments, using seed lots collected in different dates. Seeds were subjected to inducing germination treatments by chemical scarification (ACS commercial sulfuric acid, d=1,84 g/cm³ and thermic scarification (hot water. Results demonstrated high germination under acid scarification (up to 95% and inferior when submitted to thermic scarification (reaching up to 43%; witness treatments showed germination between 2% and 13%. The results confirmed the presence of seed coat dormancy. It is recommendable, to break the dormancy of lots which are similar to the investigated ones (three to 27 months after seed collection, the immersion in sulfuric acid during 30 minutes. Seeds maintained its total germinative capacity after storage for 27 months in paper bag in cold chamber (5 °C and 98 % air humidity. 
    Erythrina crista-galli L., Fabaceae, conhecida por corticeira-do-banhado, é uma árvore de porte médio, fixadora de nitrogênio, ocorrendo em vários biomas brasileiros, em terrenos alagadiços. Seu cultivo tem interesse para fins ornamentais e restauração ambiental. Informações sobre dormência tegumentar de suas sementes são conflitantes e imprecisas; por isso, o presente trabalho teve por objetivo verificá-la e, em caso positivo, definir métodos para a superação. O estudo foi composto por dois experimentos, usando lotes de sementes coletadas em datas diferentes. As sementes passaram por tratamentos de escarificação química (ácido sulfúrico comercial padrão ACS, d=1,84 g/cm³ e térmica (

  14. Regulation of Picea abies seed dormancy by red and far-red light at various moisture contents

    Energy Technology Data Exchange (ETDEWEB)

    Leinonen, K.; Chantal, M. de [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1998-04-01

    The effects of red (R), far-red (FR) and R+FR light on Norway spruce seed dormancy were studied at five different moisture contents (MC) between 5 and 20%. The degree of dormancy was studied by germinating seeds over a wide range of temperatures in the dark. The non-irradiated control seeds were shallowly dormant, only a proportion of them germinated and within a limited temperature range. Red light progressively stimulated germination between 5 and 17% MC, but this effect was reversed if a FR treatment followed, although all germination could not be inhibited by one FR pulse. Far-red light had a slightly stimulating effect at 19% MC. To generate seeds able to germinate over a wide range of temperatures in darkness, an artificial light pretreatment should be given to seeds at MC above 17% in order to receive maximum response 24 refs, 2 figs, 1 tab

  15. The consequences of seasonal fasting during the dormancy of tegu lizards (Salvator merianae) on their postprandial metabolic response.

    Science.gov (United States)

    Gavira, Rodrigo S B; Sartori, Marina R; Gontero-Fourcade, Manuel N; Gomes, Bruna F; Abe, Augusto S; Andrade, Denis V

    2018-04-19

    Tegu lizards ( Salvator merianae ) aestivate for up to 5 months during Brazil's winter, when they retreat to burrows and halt most activities. Dormant tegus reduce their gastrointestinal (GI) mass, which allows a substantial energy economy. This strategy, however, implies that the first post-dormancy digestion would be more costly than subsequent feeding episodes as a result of GI atrophy. To address this, we determined the postprandial metabolic response (SDA) of the first (M1), second (M2) and several (RM) feeding episodes after tegus' dormancy. Another group of tegus (PF) was subjected to an extra 50 day fasting period after arousal. Glucose, triglycerides and uric acid levels were checked before and after feeding. M1 digestion lasted twice as long and cost twofold more when compared with M2 or RM, in agreement with the idea that GI atrophy inflates digestion cost at the first post-dormancy meal. The SDA response was similar in M2 and RM, suggesting that the GI tract was fully reorganized after the first feeding. The SDA cost was equal in PF and RM, implying that the change in state per se (dormant to arousal) triggers the regrowth of GI, independently of feeding. Fasting tegus at M1 presented higher triglyceride and lower uric acid levels than fed tegus, indicating that fasting is mainly sustained by fat storage. Our results show that seasonal fasting imposes an extra digestion cost to tegus following their next feeding, which is fully paid during their first digestion. This surplus cost, however, is negligible compared with the overall energetic savings from GI tract atrophy during the dormancy period. © 2018. Published by The Company of Biologists Ltd.

  16. Arabidopsis IQM4, a Novel Calmodulin-Binding Protein, Is Involved With Seed Dormancy and Germination in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Yu Ping Zhou

    2018-06-01

    Full Text Available Seed dormancy and germination are regulated by complex mechanisms controlled by diverse hormones and environmental cues. Abscisic acid (ABA promotes seed dormancy and inhibits seed germination and post-germination growth. Calmodulin (CaM signals are involved with the inhibition of ABA during seed germination and seedling growth. In this study, we showed that Arabidopsis thaliana IQM4 could bind with calmodulin 5 (CaM5 both in vitro and in vivo, and that the interaction was the Ca2+-independent type. The IQM4 protein was localized in the chloroplast and the IQM4 gene was expressed in most tissues, especially the embryo and germinated seedlings. The T-DNA insertion mutants of IQM4 exhibited the reduced primary seed dormancy and lower ABA levels compared with wild type seeds. Moreover, IQM4 plays key roles in modulating the responses to ABA, salt, and osmotic stress during seed germination and post-germination growth. T-DNA insertion mutants exhibited ABA-insensitive and salt-hypersensitive phenotypes during seed germination and post-germination growth, whereas IQM4-overexpressing lines had ABA- and osmotic-hypersensitive, and salt-insensitive phenotypes. Gene expression analyses showed that mutation of IQM4 inhibited the expression of ABA biosynthetic genes NCED6 and NCED9, and seed maturation regulators LEC1, LEC2, ABI3, and ABI5 during the silique development, as well as promoted the expression of WRKY40 and inhibited that of ABI5 in ABA-regulated seed germination. These observations suggest that IQM4 is a novel Ca2+-independent CaM-binding protein, which is positively involved with seed dormancy and germination in Arabidopsis.

  17. Hollow Fiber Membrane Bioreactor Systems for Wastewater Processing: Effects of Environmental Stresses Including Dormancy Cycling and Antibiotic Dosing

    Science.gov (United States)

    Coutts, Janelle L.; Hummerick, Mary E.; Lunn, Griffin M.; Larson, Brian D.; Spencer, LaShelle E.; Kosiba, Michael L.; Khodadad, Christina L.; Catechis, John A.; Birmele, Michele N.; Wheeler, Raymond M.

    2016-01-01

    Membrane-aerated biofilm reactors (MABRs) have been studied for a number of years as an alternate approach for treating wastewater streams during space exploration. While the technology provides a promising pre-treatment for lowering organic carbon and nitrogen content without the need for harsh stabilization chemicals, several challenges must be addressed before adoption of the technology in future missions. One challenge is the transportation of bioreactors containing intact, active biofilms as a means for rapid start-up on the International Space Station or beyond. Similarly, there could be a need for placing these biological systems into a dormant state for extended periods when the system is not in use, along with the ability for rapid restart. Previous studies indicated that there was little influence of storage condition (4 or 25 C, with or without bulk fluid) on recovery of bioreactors with immature biofilms (48 days old), but that an extensive recovery time was required (20+ days). Bioreactors with fully established biofilms (13 months) were able to recover from a 7-month dormancy within 4 days (approximately 1 residence). Further dormancy and recovery testing is presented here that examines the role of biofilm age on recovery requirements, repeated dormancy cycle capabilities, and effects of long-duration dormancy cycles (8-9 months) on HFMB systems. Another challenge that must be addressed is the possibility of antibiotics entering the wastewater stream. Currently, for most laboratory tests of biological water processors, donors providing urine may not contribute to the study when taking antibiotics because the effects on the system are yet uncharacterized. A simulated urinary tract infection event, where an opportunistic, pathogenic organism, E. coli, was introduced to the HFMBs followed by dosing with an antibiotic, ciprofloxacin, was completed to study the effect of the antibiotic on reactor performance and to also examine the development of

  18. Cloning and characterization of a novel Gladiolus hybridus AFP family gene (GhAFP-like) related to corm dormancy

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jian; Seng, Shanshan [Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100193 (China); Carianopol, Carina [Department of Biological Sciences, University of Toronto, Toronto, Ontario (Canada); Sui, Juanjuan [College of Biology, Fuyang Normal College, Fuyang, Anhui (China); Yang, Qiuyan; Zhang, Fengqin; Jiang, Huiru [Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100193 (China); He, Junna, E-mail: hejunna@cau.edu.cn [Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100193 (China); Yi, Mingfang, E-mail: ymfang@cau.edu.cn [Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100193 (China)

    2016-02-26

    Abscisic acid (ABA) is an important phytohormone controlling seed dormancy. AFPs (ABA INSENSITIVE FIVE BINDING PROTEINS) are reported to be negative regulators of the ABA signaling pathway. The involvement of AFPs in dormant vegetative organs remains poorly understood. Here, we isolated and characterized a novel AFP family member from Gladiolus dormant cormels, GhAFP-like, containing three conserved domains of the AFP family. Quantitative PCR analysis revealed that GhAFP-like was expressed in dormant organs and its expression was down-regulated along with corm storage. GhAFP-like was verified to be a nuclear-localized protein. Overexpressing GhAFP-like in Arabidopsis thaliana not only showed weaker seed dormancy with insensitivity to ABA, but also changed the expression of some ABA related genes. In addition, a primary root elongation assay showed GhAFP-like may involve in auxin signaling response. The results in this study indicate that GhAFP-like acts as a negative regulator in ABA signaling and is related to dormancy. - Highlights: • GhAFP-like is expessed in dormant corm. • Overexpressing GhAFP-like showed early germination and insensitivity to ABA. • Overexpressing GhAFP-like changed ABI5 downstream genes expression.

  19. Cloning and characterization of a novel Gladiolus hybridus AFP family gene (GhAFP-like) related to corm dormancy

    International Nuclear Information System (INIS)

    Wu, Jian; Seng, Shanshan; Carianopol, Carina; Sui, Juanjuan; Yang, Qiuyan; Zhang, Fengqin; Jiang, Huiru; He, Junna; Yi, Mingfang

    2016-01-01

    Abscisic acid (ABA) is an important phytohormone controlling seed dormancy. AFPs (ABA INSENSITIVE FIVE BINDING PROTEINS) are reported to be negative regulators of the ABA signaling pathway. The involvement of AFPs in dormant vegetative organs remains poorly understood. Here, we isolated and characterized a novel AFP family member from Gladiolus dormant cormels, GhAFP-like, containing three conserved domains of the AFP family. Quantitative PCR analysis revealed that GhAFP-like was expressed in dormant organs and its expression was down-regulated along with corm storage. GhAFP-like was verified to be a nuclear-localized protein. Overexpressing GhAFP-like in Arabidopsis thaliana not only showed weaker seed dormancy with insensitivity to ABA, but also changed the expression of some ABA related genes. In addition, a primary root elongation assay showed GhAFP-like may involve in auxin signaling response. The results in this study indicate that GhAFP-like acts as a negative regulator in ABA signaling and is related to dormancy. - Highlights: • GhAFP-like is expessed in dormant corm. • Overexpressing GhAFP-like showed early germination and insensitivity to ABA. • Overexpressing GhAFP-like changed ABI5 downstream genes expression.

  20. Effects of germination season on life history traits and on transgenerational plasticity in seed dormancy in a cold desert annual.

    Science.gov (United States)

    Lu, Juan J; Tan, Dun Y; Baskin, Carol C; Baskin, Jerry M

    2016-04-27

    The maternal environment can influence the intensity of seed dormancy and thus seasonal germination timing and post-germination life history traits. We tested the hypotheses that germination season influences phenotypic expression of post-germination life history traits in the cold desert annual Isatis violascens and that plants from autumn- and spring-germinating seeds produce different proportions of seeds with nondeep and intermediate physiological dormancy (PD). Seeds were sown in summer and flexibility in various life history traits determined for plants that germinated in autumn and in spring. A higher percentage of spring- than of autumn-germinating plants survived the seedling stage, and all surviving plants reproduced. Number of silicles increased with plant size (autumn- > spring-germinating plants), whereas percent dry mass allocated to reproduction was higher in spring- than in autumn-germinating plants. Autumn-germinating plants produced proportionally more seeds with intermediate PD than spring-germinating plants, while spring-germinating plants produced proportionally more seeds with nondeep PD than autumn-germinating plants. Flexibility throughout the life history and transgenerational plasticity in seed dormancy are adaptations of I. violascens to its desert habitat. Our study is the first to demonstrate that autumn- and spring-germinating plants in a species population differ in proportion of seeds produced with different levels of PD.

  1. Integrated transcriptomic and proteomic profiling of white spruce stems during the transition from active growth to dormancy.

    Science.gov (United States)

    Galindo González, Leonardo M; El Kayal, Walid; Ju, Chelsea J-T; Allen, Carmen C G; King-Jones, Susanne; Cooke, Janice E K

    2012-04-01

    In the autumn, stems of woody perennials such as forest trees undergo a transition from active growth to dormancy. We used microarray transcriptomic profiling in combination with a proteomics analysis to elucidate processes that occur during this growth-to-dormancy transition in a conifer, white spruce (Picea glauca[Moench] Voss). Several differentially expressed genes were likely associated with the developmental transition that occurs during growth cessation in the cambial zone and the concomitant completion of cell maturation in vascular tissues. Genes encoding for cell wall and membrane biosynthetic enzymes showed transcript abundance patterns consistent with completion of cell maturation, and also of cell wall and membrane modifications potentially enabling cells to withstand the harsh conditions of winter. Several differentially expressed genes were identified that encoded putative regulators of cambial activity, cell development and of the photoperiodic pathway. Reconfiguration of carbon allocation figured centrally in the tree's overwintering preparations. For example, genes associated with carbon-based defences such as terpenoids were down-regulated, while many genes associated with protein-based defences and other stress mitigation mechanisms were up-regulated. Several of these correspond to proteins that were accumulated during the growth-to-dormancy transition, emphasizing the importance of stress protection in the tree's adaptive response to overwintering. © 2011 Blackwell Publishing Ltd.

  2. Cardiac hypertrophy and structural and metabolic remodeling related to seasonal dormancy in the first annual cycle in tegu lizards.

    Science.gov (United States)

    da Silveira, Lilian Cristina; do Nascimento, Lucas Francisco R; Colquhoun, Alison; Abe, Augusto S; de Souza, Silvia Cristina R

    2013-07-01

    Morpho-functional adjustments in the heart of juvenile tegu lizards (Tupinambis merianae) were analyzed at distinct seasonal periods to investigate how the demands of growth and of energy saving are reconciled during the first annual cycle. The relative ventricular mass (Mv) was 31% and 69% larger in late autumn and winter dormancy, respectively, compared to early autumn. This effect did not persist during unfed arousal, suggesting that protein accumulates in the heart during hypometabolism and is degraded on arousal. Both the hypertrophy and the atrophy were disproportionate in the largest individuals. In contrast, Mv was smaller in lizards that were starved during spring activity compared to fed lizards, this effect being larger in smaller individuals. In late autumn and winter dormancy the spongy myocardium had 8% of the section area covered by lacunary spaces, which expanded after food intake during arousal and reached 29% in spring activity together with higher density of cardiomyocytes. Total and soluble proteins per mass unity were unchanged, and maximum activities of selected enzymes suggest sustained glycolytic and aerobic capacities during hypometabolism. Results indicate that important structural adjustments occur in the heart in anticipation of dormancy, and that the protein balance in the tissue is maintained at winter temperatures ~17°C. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Seed maturation associated transcriptional programs and regulatory networks underlying genotypic difference in seed dormancy and size/weight in wheat (Triticum aestivum L.).

    Science.gov (United States)

    Yamasaki, Yuji; Gao, Feng; Jordan, Mark C; Ayele, Belay T

    2017-09-16

    Maturation forms one of the critical seed developmental phases and it is characterized mainly by programmed cell death, dormancy and desiccation, however, the transcriptional programs and regulatory networks underlying acquisition of dormancy and deposition of storage reserves during the maturation phase of seed development are poorly understood in wheat. The present study performed comparative spatiotemporal transcriptomic analysis of seed maturation in two wheat genotypes with contrasting seed weight/size and dormancy phenotype. The embryo and endosperm tissues of maturing seeds appeared to exhibit genotype-specific temporal shifts in gene expression profile that might contribute to the seed phenotypic variations. Functional annotations of gene clusters suggest that the two tissues exhibit distinct but genotypically overlapping molecular functions. Motif enrichment predicts genotypically distinct abscisic acid (ABA) and gibberellin (GA) regulated transcriptional networks contribute to the contrasting seed weight/size and dormancy phenotypes between the two genotypes. While other ABA responsive element (ABRE) motifs are enriched in both genotypes, the prevalence of G-box-like motif specifically in tissues of the dormant genotype suggests distinct ABA mediated transcriptional mechanisms control the establishment of dormancy during seed maturation. In agreement with this, the bZIP transcription factors that co-express with ABRE enriched embryonic genes differ with genotype. The enrichment of SITEIIATCYTC motif specifically in embryo clusters of maturing seeds irrespective of genotype predicts a tissue specific role for the respective TCP transcription factors with no or minimal contribution to the variations in seed dormancy. The results of this study advance our understanding of the seed maturation associated molecular mechanisms underlying variation in dormancy and weight/size in wheat seeds, which is a critical step towards the designing of molecular strategies

  4. The impact of global warming on germination and seedling emergence in Alliaria petiolata, a woodland species with dormancy loss dependent on low temperature.

    Science.gov (United States)

    Footitt, S; Huang, Z; Ölcer-Footitt, H; Clay, H; Finch-Savage, W E

    2018-03-23

    The impact of global warming on seed dormancy loss and germination was investigated in Alliaria petiolata (garlic mustard), a common woodland/hedgerow plant in Eurasia, considered invasive in North America. Increased temperature may have serious implications, since seeds of this species germinate and emerge at low temperatures early in spring to establish and grow before canopy development of competing species. Dormancy was evaluated in seeds buried in field soils. Seedling emergence was also investigated in the field, and in a thermogradient tunnel under global warming scenarios representing predicted UK air temperatures through to 2080. Dormancy was simple, and its relief required the accumulation of low temperature chilling time. Under a global warming scenario, dormancy relief and seedling emergence declined and seed mortality increased as soil temperature increased along a thermal gradient. Seedling emergence advanced with soil temperature, peaking 8 days earlier under 2080 conditions. The results indicate that as mean temperature increases due to global warming, the chilling requirement for dormancy relief may not be fully satisfied, but seedling emergence will continue from low dormancy seeds in the population. Adaptation resulting from selection of this low dormancy proportion is likely to reduce the overall population chilling requirement. Seedling emergence is also likely to keep pace with the advancement of biological spring, enabling A. petiolata to maintain its strategy of establishment before the woodland canopy closes. However, this potential for adaptation may be countered by increased seed mortality in the seed bank as soils warm. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  5. De novo characterization of fall dormant and nondormant alfalfa (Medicago sativa L.) leaf transcriptome and identification of candidate genes related to fall dormancy.

    Science.gov (United States)

    Zhang, Senhao; Shi, Yinghua; Cheng, Ningning; Du, Hongqi; Fan, Wenna; Wang, Chengzhang

    2015-01-01

    Alfalfa (Medicago sativa L.) is one of the most widely cultivated perennial forage legumes worldwide. Fall dormancy is an adaptive character related to the biomass production and winter survival in alfalfa. The physiological, biochemical and molecular mechanisms causing fall dormancy and the related genes have not been well studied. In this study, we sequenced two standard varieties of alfalfa (dormant and non-dormant) at two time points and generated approximately 160 million high quality paired-end sequence reads using sequencing by synthesis (SBS) technology. The de novo transcriptome assembly generated a set of 192,875 transcripts with an average length of 856 bp representing about 165.1 Mb of the alfalfa leaf transcriptome. After assembly, 111,062 (57.6%) transcripts were annotated against the NCBI non-redundant database. A total of 30,165 (15.6%) transcripts were mapped to 323 Kyoto Encyclopedia of Genes and Genomes pathways. We also identified 41,973 simple sequence repeats, which can be used to generate markers for alfalfa, and 1,541 transcription factors were identified across 1,350 transcripts. Gene expression between dormant and non-dormant alfalfa at different time points were performed, and we identified several differentially expressed genes potentially related to fall dormancy. The Gene Ontology and pathways information were also identified. We sequenced and assembled the leaf transcriptome of alfalfa related to fall dormancy, and also identified some genes of interest involved in the fall dormancy mechanism. Thus, our research focused on studying fall dormancy in alfalfa through transcriptome sequencing. The sequencing and gene expression data generated in this study may be used further to elucidate the complete mechanisms governing fall dormancy in alfalfa.

  6. Transcriptomic analysis of the underground renewal buds during dormancy transition and release in 'Hangbaishao' peony (Paeonia lactiflora.

    Directory of Open Access Journals (Sweden)

    Jiaping Zhang

    Full Text Available Paeonia lactiflora is one of the most famous species of herbaceous peonies with gorgeous flowers. Bud dormancy is a crucial developmental process that allows P. lactiflora to survive unfavorable environmental conditions. However, little information is available on the molecular mechanism of the bud dormancy in P. lactiflora. We performed de novo transcriptome sequencing using the Illumina RNA sequencing platform for the underground renewal buds of P. lactiflora 'Hangbaishao' to study the molecular mechanism underlying its bud dormancy transition (the period from endodormancy to ecodormancy and release (the period from ecodormancy to bud elongation and sprouting. Approximately 300 million high-quality clean reads were generated and assembled into 207,827 (mean length = 828 bp and 51,481 (mean length = 1250 bp unigenes using two assembly methods named "Trinity" and "Trinity+PRICE", respectively. Based on the data obtained by the latter method, 32,316 unigenes were annotated by BLAST against various databases. Approximately 1,251 putative transcription factors were obtained, of which the largest number of unique transcripts belonged to the basic helix-loop-helix protein (bHLH transcription factor family, and five of the top ten highly expressed transcripts were annotated as dehydrin (DHN. A total of 17,705 simple sequence repeat (SSR motifs distributed in 13,797 sequences were obtained. The budbreak morphology, levels of indole-3-acetic acid (IAA and abscisic acid (ABA, and activities of guaiacol peroxidase (POD and catalase (CAT were observed. The expression of 20 interested unigenes, which annotated as DHN, heat shock protein (HSP, histone, late elongated hypocotyl (LHY, and phytochrome (PHY, and so on, were also analyzed. These studies were based on morphological, physiological, biochemical, and molecular levels and provide comprehensive insight into the mechanism of dormancy transition and release in P. lactiflora. Transcriptome dataset can be

  7. ABI4 regulates primary seed dormancy by regulating the biogenesis of abscisic acid and gibberellins in arabidopsis.

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    Kai Shu

    2013-06-01

    Full Text Available Seed dormancy is an important economic trait for agricultural production. Abscisic acid (ABA and Gibberellins (GA are the primary factors that regulate the transition from dormancy to germination, and they regulate this process antagonistically. The detailed regulatory mechanism involving crosstalk between ABA and GA, which underlies seed dormancy, requires further elucidation. Here, we report that ABI4 positively regulates primary seed dormancy, while negatively regulating cotyledon greening, by mediating the biogenesis of ABA and GA. Seeds of the Arabidopsis abi4 mutant that were subjected to short-term storage (one or two weeks germinated significantly more quickly than Wild-Type (WT, and abi4 cotyledons greened markedly more quickly than WT, while the rates of germination and greening were comparable when the seeds were subjected to longer-term storage (six months. The ABA content of dry abi4 seeds was remarkably lower than that of WT, but the amounts were comparable after stratification. Consistently, the GA level of abi4 seeds was increased compared to WT. Further analysis showed that abi4 was resistant to treatment with paclobutrazol (PAC, a GA biosynthesis inhibitor, during germination, while OE-ABI4 was sensitive to PAC, and exogenous GA rescued the delayed germination phenotype of OE-ABI4. Analysis by qRT-PCR showed that the expression of genes involved in ABA and GA metabolism in dry and germinating seeds corresponded to hormonal measurements. Moreover, chromatin immunoprecipitation qPCR (ChIP-qPCR and transient expression analysis showed that ABI4 repressed CYP707A1 and CYP707A2 expression by directly binding to those promoters, and the ABI4 binding elements are essential for this repression. Accordingly, further genetic analysis showed that abi4 recovered the delayed germination phenotype of cyp707a1 and cyp707a2 and further, rescued the non-germinating phenotype of ga1-t. Taken together, this study suggests that ABI4 is a key

  8. Effects of salinity, temperature, light and dormancy regulating chemicals on seed germination of salsola drummondii ulbr

    International Nuclear Information System (INIS)

    Rasheed, A.; Hameed, A.; Khan, M.A.; Gul, B.

    2015-01-01

    Salsola drummondii Ulbr. is a perennial halophyte found in salt deserts of southern Balochistan, Pakistan. Experiments were conducted to study the effects of salinity (0, 200, 400, 600, 800 and 1000 mM NaCl), thermoperiod (10/20, 15/25, 20/30 and 25/35 degree C), light (12-h photoperiod and dark) and dormancy regulating chemicals (DRCs) on germination, recovery and viability of the seeds of S. drummondii. Seeds of S. drummondii germinated quickly in distilled water at different temperature regimes and increases in salinity decreased seed germination. Interestingly, few seeds could even germinate in 1000 mM NaCl treatment, which is about twice as high as seawater salinity. Seeds were partially photoblastic and showed relatively higher germination under 12-h photoperiod than in dark. Seeds showed poor recovery of germination from salinity and particularly when germinated in dark. Germination inhibition at high salinity (800 mM NaCl) under 12-h photoperiod was partially alleviated by the exogenous application of different DRCs, particularly fusicoccin. Moreover, all the DRCs, except GA4+7, ameliorated germination of salt stressed seeds under complete darkness and GA4 and fusicoccin were most effective. Our study shows that seeds of S. drummondii are highly tolerant to salinity and variation in temperature but partially photoblastic nature indicate that seeds will not germinate if buried under the soil. Seed germination under saline conditions can be improved by the use of DRCs particularly by application of fusicoccin. (author)

  9. VapC toxins drive cellular dormancy under uranium stress for the extreme thermoacidophile Metallosphaera prunae.

    Science.gov (United States)

    Mukherjee, Arpan; Wheaton, Garrett H; Counts, James A; Ijeomah, Brenda; Desai, Jigar; Kelly, Robert M

    2017-07-01

    When abruptly exposed to toxic levels of hexavalent uranium, the extremely thermoacidophilic archaeon Metallosphaera prunae, originally isolated from an abandoned uranium mine, ceased to grow, and concomitantly exhibited heightened levels of cytosolic ribonuclease activity that corresponded to substantial degradation of cellular RNA. The M. prunae transcriptome during 'uranium-shock' implicated VapC toxins as possible causative agents of the observed RNA degradation. Identifiable VapC toxins and PIN-domain proteins encoded in the M. prunae genome were produced and characterized, three of which (VapC4, VapC7, VapC8) substantially degraded M. prunae rRNA in vitro. RNA cleavage specificity for these VapCs mapped to motifs within M. prunae rRNA. Furthermore, based on frequency of cleavage sequences, putative target mRNAs for these VapCs were identified; these were closely associated with translation, transcription, and replication. It is interesting to note that Metallosphaera sedula, a member of the same genus and which has a nearly identical genome sequence but not isolated from a uranium-rich biotope, showed no evidence of dormancy when exposed to this metal. M. prunae utilizes VapC toxins for post-transcriptional regulation under uranium stress to enter a cellular dormant state, thereby providing an adaptive response to what would otherwise be a deleterious environmental perturbation. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  10. Garlic and H2O2 in overcoming dormancy on the vine “Cabernet Sauvignon”

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    Saavedra del Aguila Juan

    2015-01-01

    Full Text Available The objective of this experiment was to evaluate the effect of garlic extract, H2O2 and hydrogen cyanamide on dormancy break, budding and maturation of “Cabernet Sauvignon” in the Campaign Region – Brazil. In late winter 2014 and after drought pruning were performed spraying in the bud: T1 – distilled water (control; T2 – 3.0% of hydrogen cyanamide; T3 – 18.0% H2O2; and T4 – 3.0% garlic extract. It was evaluated in the field: the number of sprouted buds per plant, number of bunches per plant and weight of bunches per plant; and laboratory: on ripening, performed weekly from the color change of 360 berries per treatment for analyzes solids soluble – SS (Brix pH and titratable acidity – TA (% tartaric acid. It was observed that the vines of treatment T4 (3.0% garlic extract, showed higher percentage of buds sprouting (63 shoots plant−1. Already at the number of clusters and weight per plant, there were no statistical differences between all treatments. The results obtained in the laboratory to SS, pH and TA did not differ statistically for the four tested treatments.

  11. [Effects of fluridone, gibberellin acid and germination temperature on dormancy-breaking for Epimedium wushanense].

    Science.gov (United States)

    Su, He; Wang, Yue; Yang, Yang; Dong, Xue-Hui

    2016-07-01

    We introduced Epimedium wushanense seed which has been stratified for 90 days at 10/20 ℃ as experimental materials, with which we studied the effects of fluridone, gibberellin acid and temperature on E. wushanense germination. The results were suggested as shown below. ①Temperature, fluridone and gibberellin acid can both solely or jointly affect germination energy, germination rate significantly. Among those factors, fluridone affect germination rate and germination energy the most, followed by gibberellin acid and temperature. The highest germination rate under 4 ℃ and 10/20 ℃ stratification are 79.3%, 72.0% respectively, which resulted from treatment of F10GA300 and F20GA200 respectively. The highest germination energy under 4 ℃ and 10/20 ℃ stratification are 52.7%, 52.0%, respectively, which both resulted from F20GA200. ②Compared with 4 ℃ germination, seed could not germinate at 10/20 ℃ germination. Nontheless, application of fluridone can lead E. wushanense seeds to germinating.③The effects of gibberellin acid and interaction between gibberellin acid and fluridone significantly affect seed rotten rate during germination. In addition, soaking is another remarkable factor which increased seed rotten rate. As a result, it is feasible to promote E. wushanense dormancy releasing with gibberellin acid and fluridone associating with a proper germination temperature. Further, it is necessary taking actions to avoid seed rotten rate for saving E. wushanense nurseries'cost. Copyright© by the Chinese Pharmaceutical Association.

  12. Reduced reactivation from dormancy but maintained lineage choice of human mesenchymal stem cells with donor age.

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    Verena Dexheimer

    Full Text Available UNLABELLED: Mesenchymal stem cells (MSC are promising for cell-based regeneration therapies but up to date it is still controversial whether their function is maintained throughout ageing. Aim of this study was to address whether frequency, activation in vitro, replicative function, and in vitro lineage choice of MSC is maintained throughout ageing to answer the question whether MSC-based regeneration strategies should be restricted to younger individuals. MSC from bone marrow aspirates of 28 donors (5-80 years were characterized regarding colony-forming unit-fibroblast (CFU-F numbers, single cell cloning efficiency (SSCE, osteogenic, adipogenic and chondrogenic differentiation capacity in vitro. Alkaline phosphatase (ALP activity, mineralization, Oil Red O content, proteoglycan- and collagen type II deposition were quantified. While CFU-F frequency was maintained, SSCE and early proliferation rate decreased significantly with advanced donor age. MSC with higher proliferation rate before start of induction showed stronger osteogenic, adipogenic and chondrogenic differentiation. MSC with high osteogenic capacity underwent better chondrogenesis and showed a trend to better adipogenesis. Lineage choice was, however, unaltered with age. CONCLUSION: Ageing influenced activation from dormancy and replicative function of MSC in a way that it may be more demanding to mobilize MSC to fast cell growth at advanced age. Since fast proliferation came along with high multilineage capacity, the proliferation status of expanded MSC rather than donor age may provide an argument to restrict MSC-based therapies to certain individuals.

  13. Cyanogenic Glucosides and Derivatives in Almond and Sweet Cherry Flower Buds from Dormancy to Flowering

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    Jorge Del Cueto

    2017-05-01

    Full Text Available Almond and sweet cherry are two economically important species of the Prunus genus. They both produce the cyanogenic glucosides prunasin and amygdalin. As part of a two-component defense system, prunasin and amygdalin release toxic hydrogen cyanide upon cell disruption. In this study, we investigated the potential role within prunasin and amygdalin and some of its derivatives in endodormancy release of these two Prunus species. The content of prunasin and of endogenous prunasin turnover products in the course of flower development was examined in five almond cultivars – differing from very early to extra-late in flowering time – and in one sweet early cherry cultivar. In all cultivars, prunasin began to accumulate in the flower buds shortly after dormancy release and the levels dropped again just before flowering time. In almond and sweet cherry, the turnover of prunasin coincided with increased levels of prunasin amide whereas prunasin anitrile pentoside and β-D-glucose-1-benzoate were abundant in almond and cherry flower buds at certain developmental stages. These findings indicate a role for the turnover of cyanogenic glucosides in controlling flower development in Prunus species.

  14. The effect of fire on the dormancy break of annual legume seeds

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    Fabio Gresta

    2011-07-01

    Full Text Available Fire is a common phenomenon in the Mediterranean environment and strongly influences vegetal population dynamics through its impact on vegetation and the soil seed bank. Fire is able to break down the seed coat of hard-seeded legumes within the soil and trigger germination. To evaluate the effect of fire on the dormancy break in Medicago ciliaris, Medicago rugosa and Scorpiurus muricatus subsp. subvillosus, the seeds were placed at three different depths (surface, 25 mm and 50 mm and subjected to fires at two different intensities (high and low. As a control sample, a batch of seeds was buried at 25 mm for the duration of the trial and not subjected to fire. Soil temperatures during the fire were compared directly to stubble quantity and indirectly related to soil depth. The two Medicago species survived exposure to 90°C for a few minutes and displayed a significant increase in germination with exposure to high temperatures (over 70°C for several minutes. On the other hand, no germination occurred in Scorpiurus, irrespective of treatment. In conclusion, fire had a significant and positive effect in triggering germination of the Medicago species, but the dispersal strategies of these hard-seeded legumes are only partially interrupted by fire as a large number of seeds (>50% remained non-germinated in the soil.

  15. The effect of fire on the dormancy break of three annual legume seeds

    Directory of Open Access Journals (Sweden)

    Fabio Gresta

    2011-07-01

    Full Text Available Fire is a common phenomenon in the Mediterranean environment and strongly influences vegetal population dynamics through its impact on vegetation and the soil seed bank. Fire is able to break down the seed coat of hard-seeded legumes within the soil and trigger germination. To evaluate the effect of fire on the dormancy break in Medicago ciliaris, Medicago rugosa and Scorpiurus muricatus subsp. subvillosus, the seeds were placed at three different depths (surface, 25 mm and 50 mm and subjected to fires at two different intensities (high and low. As a control sample, a batch of seeds was buried at 25 mm for the duration of the trial and not subjected to fire. Soil temperatures during the fire were compared directly to stubble quantity and indirectly related to soil depth. The two Medicago species survived exposure to 90°C for a few minutes and displayed a significant increase in germination with exposure to high temperatures (over 70°C for several minutes. On the other hand, no germination occurred in Scorpiurus, irrespective of treatment. In conclusion, fire had a significant and positive effect in triggering germination of the Medicago species, but the dispersal strategies of these hard-seeded legumes are only partially interrupted by fire as a large number of seeds (>50% remained non-germinated in the soil.

  16. Innate immune system still works at diapause, a physiological state of dormancy in insects

    International Nuclear Information System (INIS)

    Nakamura, Akihiro; Miyado, Kenji; Takezawa, Youki; Ohnami, Naoko; Sato, Masahiro; Ono, Chihiro; Harada, Yuichirou; Yoshida, Keiichi; Kawano, Natsuko; Kanai, Seiya; Miyado, Mami; Umezawa, Akihiro

    2011-01-01

    Highlights: → Two major types of cells are present in the body fluid isolated from the thoracic region of a diapausing pupa. → Phagocytosis and encapsulation by these cells were observed when latex beads as foreign targets were microinjected into a pupa. → Such behavior by these cells was still observed even when pupae were continuously chilled at 4 o C. → Innate cellular reactions can work in diapausing insects in a dormant state. -- Abstract: Diapause is most often observed in insects and is a physiologically dormant state different from other types of dormancy, such as hibernation. It allows insects to survive in harsh environments or extend longevity. In general, larval, pupal, or adult non-diapausing insects possess an innate immune system preventing the invasion of microorganisms into their bodies; however, it is unclear whether this system works under the dormant condition of diapause. We here report the occurrence of innate cellular reactions during diapause using pupae of a giant silkmoth, Samia cynthia pryeri. Scanning electron microscopic analysis demonstrated the presence of two major types of cells in the body fluid isolated from the thoracic region of a pupa. Phagocytosis and encapsulation, characteristics of innate cellular reactions, by these cells were observed when latex beads as foreign targets were microinjected into the internal portion of a pupa. Such behavior by these cells was still observed even when pupae were continuously chilled at 4 o C. Our results indicate that innate cellular reactions can work in diapausing insects in a dormant state.

  17. Innate immune system still works at diapause, a physiological state of dormancy in insects

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Akihiro [Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535 (Japan); Miyado, Kenji, E-mail: kmiyado@nch.go.jp [Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535 (Japan); Takezawa, Youki; Ohnami, Naoko [Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535 (Japan); Sato, Masahiro [Section of Gene Expression Regulation, Frontier Science Research Center, Kagoshima University, 1-21-20 Korimoto, Kagoshima 890-0065 (Japan); Ono, Chihiro; Harada, Yuichirou; Yoshida, Keiichi; Kawano, Natsuko; Kanai, Seiya; Miyado, Mami; Umezawa, Akihiro [Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535 (Japan)

    2011-07-01

    Highlights: {yields} Two major types of cells are present in the body fluid isolated from the thoracic region of a diapausing pupa. {yields} Phagocytosis and encapsulation by these cells were observed when latex beads as foreign targets were microinjected into a pupa. {yields} Such behavior by these cells was still observed even when pupae were continuously chilled at 4 {sup o}C. {yields} Innate cellular reactions can work in diapausing insects in a dormant state. -- Abstract: Diapause is most often observed in insects and is a physiologically dormant state different from other types of dormancy, such as hibernation. It allows insects to survive in harsh environments or extend longevity. In general, larval, pupal, or adult non-diapausing insects possess an innate immune system preventing the invasion of microorganisms into their bodies; however, it is unclear whether this system works under the dormant condition of diapause. We here report the occurrence of innate cellular reactions during diapause using pupae of a giant silkmoth, Samia cynthia pryeri. Scanning electron microscopic analysis demonstrated the presence of two major types of cells in the body fluid isolated from the thoracic region of a pupa. Phagocytosis and encapsulation, characteristics of innate cellular reactions, by these cells were observed when latex beads as foreign targets were microinjected into the internal portion of a pupa. Such behavior by these cells was still observed even when pupae were continuously chilled at 4 {sup o}C. Our results indicate that innate cellular reactions can work in diapausing insects in a dormant state.

  18. DORMANCY BREAKING OF OIL PALM SEED TENERA VARIETY BY SOAKING FOR A CERTAIN LENGTH OF TIME IN THE SULFURIC ACID SOLUTION

    Directory of Open Access Journals (Sweden)

    WAYAN SUENA

    2012-11-01

    Full Text Available The experiment aimed to know the effect of length of soaked time in sulfuric acid (H2SO4 solution to the dormancy breaking upon the oil palm seeds. The experiment show that soaking seeds for 12 and 10 minutes in the acid solution resulted dormancy breaking were reached after 61.3 days, while soaking seed for 2 minutes in the same solution breaking of dormancy was reached after 73.5 days. By soaked oil palm seeds in sulfuric acid solution gave highest germination percentage (80%, peak value of germination was 0.77%/day, by an average of 0.73%/day. So that, by soaked oil palm seed in sulfuric acid solution for 12 minutes was able to increase vigor, viability, rate of germination and growth uniformity.

  19. The Effect of Seasonal Ambient Temperatures on Fire-Stimulated Germination of Species with Physiological Dormancy: A Case Study Using Boronia (Rutaceae)

    Science.gov (United States)

    Auld, Tony D.; Keith, David A.; Hui, Francis K. C.; Ooi, Mark K. J.

    2016-01-01

    Dormancy and germination requirements determine the timing and magnitude of seedling emergence, with important consequences for seedling survival and growth. Physiological dormancy is the most widespread form of dormancy in flowering plants, yet the seed ecology of species with this dormancy type is poorly understood in fire-prone vegetation. The role of seasonal temperatures as germination cues in these habitats is often overlooked due to a focus on direct fire cues such as heat shock and smoke, and little is known about the combined effects of multiple fire-related cues and environmental cues as these are seldom assessed in combination. We aimed to improve understanding of the germination requirements of species with physiological dormancy in fire-prone floras by investigating germination responses across members of the Rutaceae from south eastern Australia. We used a fully factorial experimental design to quantify the individual and combined effects of heat shock, smoke and seasonal ambient temperatures on germination of freshly dispersed seeds of seven species of Boronia, a large and difficult-to-germinate genus. Germination syndromes were highly variable but correlated with broad patterns in seed morphology and phylogenetic relationships between species. Seasonal temperatures influenced the rate and/or magnitude of germination responses in six species, and interacted with fire cues in complex ways. The combined effects of heat shock and smoke ranged from neutral to additive, synergistic, unitive or negative and varied with species, seasonal temperatures and duration of incubation. These responses could not be reliably predicted from the effect of the application of single cues. Based on these findings, fire season and fire intensity are predicted to affect both the magnitude and timing of seedling emergence in wild populations of species with physiological dormancy, with important implications for current fire management practices and for population

  20. Seed dormancy, seedling establishment and dynamics of the soil seed bank of Stipa bungeana (Poaceae on the Loess Plateau of northwestern China.

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    Xiao Wen Hu

    Full Text Available Studying seed dormancy and its consequent effect can provide important information for vegetation restoration and management. The present study investigated seed dormancy, seedling emergence and seed survival in the soil seed bank of Stipa bungeana, a grass species used in restoration of degraded land on the Loess Plateau in northwest China. Dormancy of fresh seeds was determined by incubation of seeds over a range of temperatures in both light and dark. Seed germination was evaluated after mechanical removal of palea and lemma (hulls, chemical scarification and dry storage. Fresh and one-year-stored seeds were sown in the field, and seedling emergence was monitored weekly for 8 weeks. Furthermore, seeds were buried at different soil depths, and then retrieved every 1 or 2 months to determine seed dormancy and seed viability in the laboratory. Fresh seeds (caryopses enclosed by palea and lemma had non-deep physiological dormancy. Removal of palea and lemma, chemical scarification, dry storage (afterripening, gibberellin (GA3 and potassium nitrate (KNO3 significantly improved germination. Dormancy was completely released by removal of the hulls, but seeds on which hulls were put back to their original position germinated to only 46%. Pretreatment of seeds with a 30% NaOH solution for 60 min increased germination from 25% to 82%. Speed of seedling emergence from fresh seeds was significantly lower than that of seeds stored for 1 year. However, final percentage of seedling emergence did not differ significantly for seeds sown at depths of 0 and 1 cm. Most fresh seeds of S. bungeana buried in the field in early July either had germinated or lost viability by September. All seeds buried at a depth of 5 cm had lost viability after 5 months, whereas 12% and 4% seeds of those sown on the soil surface were viable after 5 and 12 months, respectively.

  1. Seed Dormancy in Arabidopsis Requires Self-Binding Ability of DOG1 Protein and the Presence of Multiple Isoforms Generated by Alternative Splicing.

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    Kazumi Nakabayashi

    2015-12-01

    Full Text Available The Arabidopsis protein DELAY OF GERMINATION 1 (DOG1 is a key regulator of seed dormancy, which is a life history trait that determines the timing of seedling emergence. The amount of DOG1 protein in freshly harvested seeds determines their dormancy level. DOG1 has been identified as a major dormancy QTL and variation in DOG1 transcript levels between accessions contributes to natural variation for seed dormancy. The DOG1 gene is alternatively spliced. Alternative splicing increases the transcriptome and proteome diversity in higher eukaryotes by producing transcripts that encode for proteins with altered or lost function. It can also generate tissue specific transcripts or affect mRNA stability. Here we suggest a different role for alternative splicing of the DOG1 gene. DOG1 produces five transcript variants encoding three protein isoforms. Transgenic dog1 mutant seeds expressing single DOG1 transcript variants from the endogenous DOG1 promoter did not complement because they were non-dormant and lacked DOG1 protein. However, transgenic plants overexpressing single DOG1 variants from the 35S promoter could accumulate protein and showed complementation. Simultaneous expression of two or more DOG1 transcript variants from the endogenous DOG1 promoter also led to increased dormancy levels and accumulation of DOG1 protein. This suggests that single isoforms are functional, but require the presence of additional isoforms to prevent protein degradation. Subsequently, we found that the DOG1 protein can bind to itself and that this binding is required for DOG1 function but not for protein accumulation. Natural variation for DOG1 binding efficiency was observed among Arabidopsis accessions and contributes to variation in seed dormancy.

  2. Dormancy alleviation by NO or HCN leading to decline of protein carbonylation levels in apple (Malus domestica Borkh.) embryos.

    Science.gov (United States)

    Krasuska, Urszula; Ciacka, Katarzyna; Dębska, Karolina; Bogatek, Renata; Gniazdowska, Agnieszka

    2014-08-15

    Deep dormancy of apple (Malus domestica Borkh.) embryos can be overcome by short-term pre-treatment with nitric oxide (NO) or hydrogen cyanide (HCN). Dormancy alleviation of embryos modulated by NO or HCN and the first step of germination depend on temporary increased production of reactive oxygen species (ROS). Direct oxidative attack on some amino acid residues or secondary reactions via reactive carbohydrates and lipids can lead to the formation of protein carbonyl derivatives. Protein carbonylation is a widely accepted covalent and irreversible modification resulting in inhibition or alteration of enzyme/protein activities. It also increases the susceptibility of proteins to proteolytic degradation. The aim of this work was to investigate protein carbonylation in germinating apple embryos, the dormancy of which was removed by pre-treatment with NO or HCN donors. It was performed using a quantitative spectrophotometric method, while patterns of carbonylated protein in embryo axes were analyzed by immunochemical techniques. The highest concentration of protein carbonyl groups was observed in dormant embryos. It declined in germinating embryos pre-treated with NO or HCN, suggesting elevated degradation of modified proteins during seedling formation. A decrease in the concentration of carbonylated proteins was accompanied by modification in proteolytic activity in germinating apple embryos. A strict correlation between the level of protein carbonyl groups and cotyledon growth and greening was detected. Moreover, direct in vitro carbonylation of BSA treated with NO or HCN donors was analyzed, showing action of both signaling molecules as protein oxidation agents. Copyright © 2014 Elsevier GmbH. All rights reserved.

  3. Diapause and quiescence: dormancy mechanisms that contribute to the geographical expansion of mosquitoes and their evolutionary success.

    Science.gov (United States)

    Diniz, Diego Felipe Araujo; de Albuquerque, Cleide Maria Ribeiro; Oliva, Luciana Oliveira; de Melo-Santos, Maria Alice Varjal; Ayres, Constância Flávia Junqueira

    2017-06-26

    Mosquitoes are insects belonging to the order Diptera and family Culicidae. They are distributed worldwide and include approximately 3500 species, of which about 300 have medical and veterinary importance. The evolutionary success of mosquitoes, in both tropical and temperate regions, is due to the various survival strategies these insects have developed throughout their life histories. Of the many adaptive mechanisms, diapause and quiescence, two different types of dormancy, likely contribute to the establishment, maintenance and spread of natural mosquito populations. This review seeks to objectively and coherently describe the terms diapause and quiescence, which can be confused in the literature because the phenotypic effects of these mechanisms are often similar.

  4. EFFECTS OF STORAGE PERIODS AND METHODS OF OVERCOMING DORMANCY IN SEEDS OF PASSIFLORA

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    Telma Miranda dos Santos

    2012-07-01

    Full Text Available The aim of this work was to evaluate the effects of storage period and treatement with hot water at 50ºC or scarification on dormancy break down on Passiflora mucronata seeds. The storage periods were 0, 1, 4 and 12 months. The seeds were sown onto Germitest paper roll and incubated in a germination chamber under 20ºC/8h-30ºC/16h alternate temperature, at 16-h photoperiod (fluorescent light at 32 mol m-2 s-1 irradiance. The percent germination was evaluated, and the seeds germinated on moistened Germitest paper rolls in distilled water at a ratio of two and a half times the paper weight. The seeds were transferred to a germination chamber with alternating temperatures of 20-30º C and photoperiod of 16 h until the end of the experiment at 31 days. The experiment was analyzed as completely randomized designed with four replications, in which each plot was constituted by 50 seeds. The storage periods had significant effect on the variable studied, where the higher germination was obtained at freshly harvested seeds. At the first month of evaluation the germination decreased. After 4 and 12 months of storage, no germination was detected. The treatment with hot water at 50º or scarification favored the germination of the Passiflora seeds stored by one and four months, however even with the stimulus of the treatments, the values of final germination were low. The treatments were not efficient to stimulate the seed germination stored by 12 months.

  5. Changes in endogenous abscisic acid levels during dormancy release and maintenance of mature seeds: studies with the Cape Verde Islands ecotype, the dormant model of Arabidopsis thaliana.

    Science.gov (United States)

    Ali-Rachedi, Sonia; Bouinot, Denise; Wagner, Marie-Hélène; Bonnet, Magda; Sotta, Bruno; Grappin, Philippe; Jullien, Marc

    2004-07-01

    Mature seeds of the Cape Verde Islands (Cvi) ecotype of Arabidopsis thaliana (L.) Heynh. show a very marked dormancy. Dormant (D) seeds completely fail to germinate in conditions that are favourable for germination whereas non-dormant (ND) seeds germinate easily. Cvi seed dormancy is alleviated by after-ripening, stratification, and also by nitrate or fluridone treatment. Addition of gibberellins to D seeds does not suppress dormancy efficiently, suggesting that gibberellins are not directly involved in the breaking of dormancy. Dormancy expression of Cvi seeds is strongly dependent on temperature: D seeds do not germinate at warm temperatures (20-27 degrees C) but do so easily at a low temperature (13 degrees C) or when a fluridone treatment is given to D seeds sown at high temperature. To investigate the role of abscisic acid (ABA) in dormancy release and maintenance, we measured the ABA content in both ND and D seeds imbibed using various dormancy-breaking conditions. It was found that dry D seeds contained higher amounts of ABA than dry ND after-ripened seeds. During early imbibition in standard conditions, there was a decrease in ABA content in both seeds, the rate of which was slower in D seeds. Three days after sowing, the ABA content in D seeds increased specifically and then remained at a high level. When imbibed with fluridone, nitrate or stratified, the ABA content of D seeds decreased and reached a level very near to that of ND seeds. In contrast, gibberellic acid (GA3) treatment caused a transient increase in ABA content. When D seeds were sown at low optimal temperature their ABA content also decreased to the level observed in ND seeds. The present study indicates that Cvi D and ND seeds can be easily distinguished by their ability to synthesize ABA following imbibition. Treatments used here to break dormancy reduced the ABA level in imbibed D seeds to the level observed in ND seeds, with the exception of GA3 treatment, which was active in promoting

  6. Effect of Different Dormancy Breaking Treatments on Seed Germination of Salsifis (Teragopogon collinus and Flixweed ( Descurainia Sophia as Two Weed Species

    Directory of Open Access Journals (Sweden)

    marzie mazhari

    2017-01-01

    Full Text Available Introduction: Weeds limit crops growth, development and yield through adjacency and competing and seed dormancy is a problem in controlling of weeds. Man has been always tried to optimize crop yield through weeds controlling. Weeds seed bank in the soil can affected weed management and their control methods. So identifying seed bank characters has important role in choice of management methods in seeds of many plant species which cannot germinate despite favorable environmental conditions. Main reasons for this problem, which is termed as seed dormancy, are hard and impermeable seed coat and presence of immature or dormant embryo. To break dormancy, a variety of methods are in vogue worldwide these days. Of all different methods of breaking dormancy, treatment of seed with certain chemicals including different types of plant growth regulators (PGRs is contemplated as the most effective one. Gibberellic acid (GA3 is the most widely used PGR to improve seed germination in different plant species. Also, nitrate (such as KNO3 clearly stimulates the germination of dormant seeds. KNO3 is the most widely used chemical for promoting germination. Solutions of KNO3 are common in routine germination testing and are recommended by the Association of Official Seed Analysts and the International Seed Testing Association (ISTA for germination tests of many species.Stratification refers to the method of placing seeds in layers alternating with layers of a moisture retaining medium, such as sand, peat or vermiculite, and keeping them at a cool temperature for a certain period, but it varies considerably from species to species. The combination of high moisture and low temperature appears to trigger off biochemical changes which transform complex food substances into simpler forms utilized by the embryo when it renews growth at germination. The use of the word “stratification” has recently been extended to include all forms of cold, moist treatment whether or

  7. An Advanced Backcross Population through Synthetic Octaploid Wheat as a “Bridge”: Development and QTL Detection for Seed Dormancy

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    Zhang Dale

    2017-12-01

    Full Text Available The seed dormancy characteristic is regarded as one of the most critical factors for pre-harvest sprouting (PHS resistance. As a wild wheat relative species, Aegilops tauschii is a potential genetic resource for improving common wheat. In this study, an advanced backcross population (201 strains containing only Ae. tauschii segments was developed by means of synthetic octaploid wheat (hexaploid wheat Zhoumai 18 × Ae. tauschii T093. Subsequently, seed dormancy rate (Dor in the advanced backcross population was evaluated on the day 3, 5 and 7, in which 2 major QTLs (QDor-2D and QDor-3D were observed on chromosomes 2D and 3D with phenotypic variance explained values (PVEs of 10.25 and 20.40%, respectively. Further investigation revealed significant correlation between QDor-3D and Tamyb10 gene, while no association was found between the former and TaVp1 gene, implying that QDor-3D site could be of closer position to Tamyb10. The obtained quantitative trait locus sites (QTLs in this work could be applied to develop wheat cultivars with PHS resistance.

  8. Predicted global warming scenarios impact on the mother plant to alter seed dormancy and germination behaviour in Arabidopsis.

    Science.gov (United States)

    Huang, Z; Footitt, S; Tang, A; Finch-Savage, W E

    2018-01-01

    Seed characteristics are key components of plant fitness that are influenced by temperature in their maternal environment, and temperature will change with global warming. To study the effect of such temperature changes, Arabidopsis thaliana plants were grown to produce seeds along a uniquely designed polyethylene tunnel having a thermal gradient reflecting local global warming predictions. Plants therefore experienced the same variations in temperature and light conditions but different mean temperatures. A range of seed-related plant fitness estimates were measured. There were dramatic non-linear temperature effects on the germination behaviour in two contrasting ecotypes. Maternal temperatures lower than 15-16 °C resulted in significantly greater primary dormancy. In addition, the impact of nitrate in the growing media on dormancy was shown only by seeds produced below 15-16 °C. However, there were no consistent effects on seed yield, number, or size. Effects on germination behaviour were shown to be a species characteristic responding to temperature and not time of year. Elevating temperature above this critical value during seed development has the potential to dramatically alter the timing of subsequent seed germination and the proportion entering the soil seed bank. This has potential consequences for the whole plant life cycle and species fitness. © 2017 John Wiley & Sons Ltd.

  9. Overexpression of a peach CBF gene in apple: a model for understanding the integration of growth, dormancy, and cold hardiness in woody plants

    Science.gov (United States)

    The timing of cold acclimation and de-acclimation, dormancy, and bud break play an integral role in the life cycle of woody plants. The molecular events that regulate these parameters have been the subject of much study, however, in most studies these events have been investigated independently of ...

  10. Selected Plant Metabolites Involved in Oxidation-Reduction Processes during Bud Dormancy and Ontogenetic Development in Sweet Cherry Buds (Prunus avium L.

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    Susanne Baldermann

    2018-05-01

    Full Text Available Many biochemical processes are involved in regulating the consecutive transition of different phases of dormancy in sweet cherry buds. An evaluation based on a metabolic approach has, as yet, only been partly addressed. The aim of this work, therefore, was to determine which plant metabolites could serve as biomarkers for the different transitions in sweet cherry buds. The focus here was on those metabolites involved in oxidation-reduction processes during bud dormancy, as determined by targeted and untargeted mass spectrometry-based methods. The metabolites addressed included phenolic compounds, ascorbate/dehydroascorbate, reducing sugars, carotenoids and chlorophylls. The results demonstrate that the content of phenolic compounds decrease until the end of endodormancy. After a long period of constancy until the end of ecodormancy, a final phase of further decrease followed up to the phenophase open cluster. The main phenolic compounds were caffeoylquinic acids, coumaroylquinic acids and catechins, as well as quercetin and kaempferol derivatives. The data also support the protective role of ascorbate and glutathione in the para- and endodormancy phases. Consistent trends in the content of reducing sugars can be elucidated for the different phenophases of dormancy, too. The untargeted approach with principle component analysis (PCA clearly differentiates the different timings of dormancy giving further valuable information.

  11. Differentiated dynamics of bud dormancy and growth in temperate fruit trees relating to bud phenology adaptation, the case of apple and almond trees

    Science.gov (United States)

    El Yaacoubi, Adnane; Malagi, Gustavo; Oukabli, Ahmed; Citadin, Idemir; Hafidi, Majida; Bonhomme, Marc; Legave, Jean-Michel

    2016-11-01

    Few studies have focused on the characterization of bud dormancy and growth dynamics for temperate fruit species in temperate and mild cropping areas, although this is an appropriate framework to anticipate phenology adaptation facing future warming contexts which would potentially combine chill declines and heat increases. To examine this issue, two experimental approaches and field observations were used for high- and low-chill apple cultivars in temperate climate of southern France and in mild climates of northern Morocco and southern Brazil. Low-chill almond cultivars offered an additional relevant plant material for comparison with apple in northern Morocco. Divergent patterns of dormancy and growth dynamics were clearly found in apple tree between southern France and southern Brazil. Divergences were less pronounced between France and Morocco. A global view outlined main differences in the dormancy chronology and intensity, the transition between endordormancy and ecodormancy and the duration of ecodormancy. A key role of bud rehydration in the transition period was shown. High-chill cultivars would be submitted in mild conditions to heterogeneous rehydration capacities linked to insufficient chill fulfillment and excessive forcing linked to high temperatures. This would favor bud competitions and consequently excessive flowering durations and weak flowering. Low chilling requirements in apple and almond would conversely confer biological capacities to tolerate superficial dormancy and abrupt transition from endordormancy to ecodormancy without important heterogeneous rehydration states within buds. It may also assume that low-chill cultivars can also tolerate high temperatures during ecodormancy as well as extended flowering durations.

  12. Differentiated dynamics of bud dormancy and growth in temperate fruit trees relating to bud phenology adaptation, the case of apple and almond trees.

    Science.gov (United States)

    El Yaacoubi, Adnane; Malagi, Gustavo; Oukabli, Ahmed; Citadin, Idemir; Hafidi, Majida; Bonhomme, Marc; Legave, Jean-Michel

    2016-11-01

    Few studies have focused on the characterization of bud dormancy and growth dynamics for temperate fruit species in temperate and mild cropping areas, although this is an appropriate framework to anticipate phenology adaptation facing future warming contexts which would potentially combine chill declines and heat increases. To examine this issue, two experimental approaches and field observations were used for high- and low-chill apple cultivars in temperate climate of southern France and in mild climates of northern Morocco and southern Brazil. Low-chill almond cultivars offered an additional relevant plant material for comparison with apple in northern Morocco. Divergent patterns of dormancy and growth dynamics were clearly found in apple tree between southern France and southern Brazil. Divergences were less pronounced between France and Morocco. A global view outlined main differences in the dormancy chronology and intensity, the transition between endordormancy and ecodormancy and the duration of ecodormancy. A key role of bud rehydration in the transition period was shown. High-chill cultivars would be submitted in mild conditions to heterogeneous rehydration capacities linked to insufficient chill fulfillment and excessive forcing linked to high temperatures. This would favor bud competitions and consequently excessive flowering durations and weak flowering. Low chilling requirements in apple and almond would conversely confer biological capacities to tolerate superficial dormancy and abrupt transition from endordormancy to ecodormancy without important heterogeneous rehydration states within buds. It may also assume that low-chill cultivars can also tolerate high temperatures during ecodormancy as well as extended flowering durations.

  13. Seed dormancy release in Arabidopsis Cvi by dry after-ripening, low temperature, nitrate and light shows common quantitative patterns of gene expression directed by environment specific sensing

    NARCIS (Netherlands)

    Finch-Savage, W.E.; Cadman, C.S.C.; Toorop, P.E.; Lynn, J.R.; Hilhorst, H.W.M.

    2007-01-01

    The depth of seed dormancy can be influenced by a number of different environmental signals, but whether a common mechanism underlies this apparently similar response has yet to be investigated. Full-genome microarrays were used for a global transcript analysis of Arabidopsis thaliana Cape Verde

  14. Transcriptome and Metabolite Changes during Hydrogen Cyanamide-Induced Floral Bud Break in Sweet Cherry.

    Science.gov (United States)

    Ionescu, Irina A; López-Ortega, Gregorio; Burow, Meike; Bayo-Canha, Almudena; Junge, Alexander; Gericke, Oliver; Møller, Birger L; Sánchez-Pérez, Raquel

    2017-01-01

    Release of bud dormancy in perennial woody plants is a temperature-dependent process and thus flowering in these species is heavily affected by climate change. The lack of cold winters in temperate growing regions often results in reduced flowering and low fruit yields. This is likely to decrease the availability of fruits and nuts of the Prunus spp. in the near future. In order to maintain high yields, it is crucial to gain detailed knowledge on the molecular mechanisms controlling the release of bud dormancy. Here, we studied these mechanisms using sweet cherry ( Prunus avium L.), a crop where the agrochemical hydrogen cyanamide (HC) is routinely used to compensate for the lack of cold winter temperatures and to induce flower opening. In this work, dormant flower buds were sprayed with hydrogen cyanamide followed by deep RNA sequencing, identifying three main expression patterns in response to HC. These transcript level results were validated by quantitative real time polymerase chain reaction and supported further by phytohormone profiling (ABA, SA, IAA, CK, ethylene, JA). Using these approaches, we identified the most up-regulated pathways: the cytokinin pathway, as well as the jasmonate and the hydrogen cyanide pathway. Our results strongly suggest an inductive effect of these metabolites in bud dormancy release and provide a stepping stone for the characterization of key genes in bud dormancy release.

  15. Transcriptome and Metabolite Changes during Hydrogen Cyanamide-Induced Floral Bud Break in Sweet Cherry

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    Irina A. Ionescu

    2017-07-01

    Full Text Available Release of bud dormancy in perennial woody plants is a temperature-dependent process and thus flowering in these species is heavily affected by climate change. The lack of cold winters in temperate growing regions often results in reduced flowering and low fruit yields. This is likely to decrease the availability of fruits and nuts of the Prunus spp. in the near future. In order to maintain high yields, it is crucial to gain detailed knowledge on the molecular mechanisms controlling the release of bud dormancy. Here, we studied these mechanisms using sweet cherry (Prunus avium L., a crop where the agrochemical hydrogen cyanamide (HC is routinely used to compensate for the lack of cold winter temperatures and to induce flower opening. In this work, dormant flower buds were sprayed with hydrogen cyanamide followed by deep RNA sequencing, identifying three main expression patterns in response to HC. These transcript level results were validated by quantitative real time polymerase chain reaction and supported further by phytohormone profiling (ABA, SA, IAA, CK, ethylene, JA. Using these approaches, we identified the most up-regulated pathways: the cytokinin pathway, as well as the jasmonate and the hydrogen cyanide pathway. Our results strongly suggest an inductive effect of these metabolites in bud dormancy release and provide a stepping stone for the characterization of key genes in bud dormancy release.

  16. Overcoming seed dormancy using gibberellic acid and the performance of young Syagrus coronata plants under severe drought stress and recovery.

    Science.gov (United States)

    Medeiros, Maria J; Oliveira, Marciel T; Willadino, Lilia; Santos, Mauro G

    2015-12-01

    Syagrus coronata, a native palm tree of the Brazilian semi-arid region, exhibits low germinability due to seed dormancy. This study aimed to increase the germinability, analyze the morphology of seedlings and evaluate the performance of young plants under a water deficit. We used immersion in water and gibberellic acid (GA3) as pyrene (seed with endocarp) pre-germination treatments, and we analyzed the water relations, gas exchange, chlorophyll fluorescence and carbon balance components of young plants under drought and rehydration conditions. The immersion of pyrenes in 0.3 mM GA3 solution for 24 h enhanced the emergence and survival of plants and the emergence rate index. The germination of S. coronata is of the remote tubular type, and seedling growth originates with the protrusion of the cotyledon petiole, followed by the subsequent emergence of the root, leaf sheaths and eophyll. The plants exhibited high tolerance to no irrigation for 37 days, which was attributed to strong stomatal control, a higher proportion of energy dissipation and a higher content of photoprotective pigments. Despite the reduced stomatal conductance (regardless of soil water availability), the photosynthetic rate remained high throughout the day, which indicated a low correlation between these two parameters. After rehydration, we observed that both the leaf water content and photosynthesis recovered, which showed an absence of irreversible damage of the photosynthetic apparatus. The use of 0.3 mM GA3 is recommended as a treatment for overcoming seed dormancy in this species. Young S. coronata plants showed high tolerance during drought and resilience after rehydration by adjusting their leaf metabolism, which could explain the endemism of this species in semi-arid regions and its ability to remain evergreen throughout the year. Furthermore, with high photosynthetic rate in the most favorable time of day, even under drought stress. Copyright © 2015 Elsevier Masson SAS. All rights

  17. INTRA-AND INTER-POPULATION VARIATION IN SEED SIZE AND DORMANCY IN Schizolobium parahyba (Vell. Blake IN THE ATLANTIC FOREST

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    Juliana Müller Freire

    2015-01-01

    Full Text Available Seed size and dormancy level were studied in 20 trees from two populations of Schizolobium parahybato evaluate how these characteristics occurbetween and within populations, and whether seed germination was affected by its morphometry. These two populations are located in the coastal (Paraty or mountain (Miguel Pereira regions in the state of Rio de Janeiro, Brazil. The seed morphometrictraits (length, width, thickness and weight were measured. Germination with or without seedcoatdormancy treatment (mechanical scarification wasassessedbya randomized emergence test in nursey. All morphometric traits differed significantly among individuals and between populations. The trees from the mountain region showed a larger seed size and a lower dormancy level than that of trees from the coastal region. Seed size had no effect on seed germination or seedling development. Climate influence on the determination of germination behavior is discussed based on the results.

  18. Reference gene selection for molecular studies of dormancy in wild oat (Avena fatua L. caryopses by RT-qPCR method.

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    Izabela Ruduś

    Full Text Available Molecular studies of primary and secondary dormancy in Avena fatua L., a serious weed of cereal and other crops, are intended to reveal the species-specific details of underlying molecular mechanisms which in turn may be useable in weed management. Among others, quantitative real-time PCR (RT-qPCR data of comparative gene expression analysis may give some insight into the involvement of particular wild oat genes in dormancy release, maintenance or induction by unfavorable conditions. To assure obtaining biologically significant results using this method, the expression stability of selected candidate reference genes in different data subsets was evaluated using four statistical algorithms i.e. geNorm, NormFinder, Best Keeper and ΔCt method. Although some discrepancies in their ranking outputs were noticed, evidently two ubiquitin-conjugating enzyme homologs, AfUBC1 and AfUBC2, as well as one homolog of glyceraldehyde 3-phosphate dehydrogenase AfGAPDH1 and TATA-binding protein AfTBP2 appeared as more stably expressed than AfEF1a (translation elongation factor 1α, AfGAPDH2 or the least stable α-tubulin homolog AfTUA1 in caryopses and seedlings of A. fatua. Gene expression analysis of a dormancy-related wild oat transcription factor VIVIPAROUS1 (AfVP1 allowed for a validation of candidate reference genes performance. Based on the obtained results it can be recommended that the normalization factor calculated as a geometric mean of Cq values of AfUBC1, AfUBC2 and AfGAPDH1 would be optimal for RT-qPCR results normalization in the experiments comprising A. fatua caryopses of different dormancy status.

  19. Reference gene selection for molecular studies of dormancy in wild oat (Avena fatua L.) caryopses by RT-qPCR method.

    Science.gov (United States)

    Ruduś, Izabela; Kępczyński, Jan

    2018-01-01

    Molecular studies of primary and secondary dormancy in Avena fatua L., a serious weed of cereal and other crops, are intended to reveal the species-specific details of underlying molecular mechanisms which in turn may be useable in weed management. Among others, quantitative real-time PCR (RT-qPCR) data of comparative gene expression analysis may give some insight into the involvement of particular wild oat genes in dormancy release, maintenance or induction by unfavorable conditions. To assure obtaining biologically significant results using this method, the expression stability of selected candidate reference genes in different data subsets was evaluated using four statistical algorithms i.e. geNorm, NormFinder, Best Keeper and ΔCt method. Although some discrepancies in their ranking outputs were noticed, evidently two ubiquitin-conjugating enzyme homologs, AfUBC1 and AfUBC2, as well as one homolog of glyceraldehyde 3-phosphate dehydrogenase AfGAPDH1 and TATA-binding protein AfTBP2 appeared as more stably expressed than AfEF1a (translation elongation factor 1α), AfGAPDH2 or the least stable α-tubulin homolog AfTUA1 in caryopses and seedlings of A. fatua. Gene expression analysis of a dormancy-related wild oat transcription factor VIVIPAROUS1 (AfVP1) allowed for a validation of candidate reference genes performance. Based on the obtained results it can be recommended that the normalization factor calculated as a geometric mean of Cq values of AfUBC1, AfUBC2 and AfGAPDH1 would be optimal for RT-qPCR results normalization in the experiments comprising A. fatua caryopses of different dormancy status.

  20. Storage behavior and changes in concentrations of abscisic acid and gibberellins during dormancy break and germination in seeds of Phellodendron amurense var. wilsonii (Rutaceae).

    Science.gov (United States)

    Chen, Shun-Ying; Chien, Ching-Te; Baskin, Jerry M; Baskin, Carol C

    2010-02-01

    The medicinal Asian plant genus Phellodendron is known to contain several very important compounds that have biological action. The main purpose of this study was to determine whether seeds of Phellodendron amurense var. wilsonii can be stored and to characterize their dormancy. Seeds of this taxon stored at -20 and -80 degrees C and in liquid nitrogen retained their high germinability, indicating that they have orthodox storage behavior. Intact seeds from freshly collected fruits were dormant and required 12 weeks of cold stratification at 4 degrees C for complete germination. Scarifying the seed coat was partially effective in breaking seed dormancy. Exogenous gibberellins (GA(3), GA(4) and GA(4+7)) promoted germination of scarified seeds, GA(4) and GA(4+7) being more effective than GA(3). Fluridone, an abscisic acid (ABA) biosynthesis inhibitor, was efficient in breaking dormancy, but it was less effective than GA(4) or GA(4+7) alone. Paclobutrazol, a GA biosynthesis inhibitor, inhibited seed germination, and the inhibitory effect was reversed completely by GA(4) and by GA(4+7). ABA content of seeds subjected to cold stratification or to incubation at 35/10 degrees C, which enhanced seed germination, was reduced about four- to sixfold compared to that of fresh seeds. Higher concentrations of GA(3), GA(4) and GA(7) were detected in nondormant seeds and in seeds with an emerged radicle than in fresh seeds. Present results seem to indicate that dormancy in P. amurense var. wilsonii seeds is imposed partially by the seed coat and partially by high ABA content. ABA content decreased and GA(3), GA(4) and GA(7) content increased during germination.

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

    OpenAIRE

    Graeber, K.; Linkies, A.; Steinbrecher, T.; Tarkowská, D. (Danuše); Turečková, V. (Veronika); Ignatz, M.; Voegele, A.; Urbanová, T. (Terezie); Strnad, M. (Miroslav); Leubner-Metzger, G. (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-swapp...

  2. Pemecahan Dormansi Dan Perkecambahan Asam Kuranji (Dialium Indum L.) Secara Mekanis Dan Kimiawi Breaking Dormancy and Seeds Germination of Asam Kuranji (Dialium Indum L.) with Mechanical and Chemical

    OpenAIRE

    Ismuhajaroh, Bakti Nur

    2014-01-01

    The purpose of the study was to find out the dormancy breaking and the seed germination of Asam kuranji (Dialium indum L.) mechanically by sandpapering the seeds and chemically by immersing them in sulfuric acid (H2SO4). The experiment was conducted at the Plant Physiology Laboratory of Agricultural Faculty of Lambung Mangkurat University from June - August 2013 using Completely Randomized Design (CRD) with 2 x 4 factorial. The first factor was the mechanical treatment  (s0 = without sandpape...

  3. Seed Germination Ecology of the Cold Desert Annual Isatis violascens (Brassicaceae: Two Levels of Physiological Dormancy and Role of the Pericarp.

    Directory of Open Access Journals (Sweden)

    Yuan M Zhou

    Full Text Available The occurrence of various species of Brassicaceae with indehiscent fruits in the cold deserts of NW China suggests that there are adaptive advantages of this trait. We hypothesized that the pericarp of the single-seeded silicles of Isatis violascens restricts embryo expansion and thus prevents germination for 1 or more years. Thus, our aim was to investigate the role of the pericarp in seed dormancy and germination of this species. The effects of afterripening, treatment with gibberellic acid (GA3 and cold stratification on seed dormancy-break were tested using intact silicles and isolated seeds, and germination phenology was monitored in an experimental garden. The pericarp has a role in mechanically inhibiting germination of fresh seeds and promotes germination of nondormant seeds, but it does not facilitate formation of a persistent seed bank. Seeds in silicles in watered soil began to germinate earlier in autumn and germinated to higher percentages than isolated seeds. Sixty-two percent of seeds in the buried silicles germinated by the end of the first spring, and only 3% remained nongerminated and viable. Twenty to twenty-five percent of the seeds have nondeep physiological dormancy (PD and 75-80% intermediate PD. Seeds with nondeep PD afterripen in summer and germinate inside the silicles in autumn if the soil is moist. Afterripening during summer significantly decreased the amount of cold stratification required to break intermediate PD. The presence of both nondeep and intermediate PD in the seed cohort may be a bet-hedging strategy.

  4. Time indices of multiphasic development in genotypes of sweet cherry are similar from dormancy to cessation of pit growth.

    Science.gov (United States)

    Gibeaut, David M; Whiting, Matthew D; Einhorn, Todd

    2017-02-01

    The archetypical double sigmoid-shaped growth curve of the sweet cherry drupe (Prunus avium) does not address critical development from eco-dormancy to anthesis and has not been correlated to reproductive bud development. Accurate representation of the growth and development of post-anthesis ovaries is confounded by anthesis timing, fruiting-density and the presence of unfertilized and defective ovaries whose growth differs from those that persist to maturation. These factors were addressed to assess pre-anthesis and full-season growth and development of three sweet cherry cultivars, 'Chelan', 'Bing' and 'Sweetheart', differing primarily in seasonal duration and fruit size. Volume was calculated from photographic measurements of reproductive buds, ovaries and pits at all phases of development. A population of unfertilized ovaries was produced using bee-exclusion netting to enable a statistical comparison with an open pollinated population to detect differences in size and shape between successful and failing fruit growth. Anthesis timing and fruiting-density were manipulated by floral extinction at the spur and whole-tree scales. Developmental time indices were analysed using polynomial curve fitting of log-transformed data supported by Richards and logistic functions of asymptotic growth of the pit and maturing fruit, respectively. Pre-anthesis growth began at the completion of eco-dormancy. A slight decline in relative growth rate (RGR) was observed during bud scale separation approx. -16 d from anthesis (DFA) before resumption of exponential growth to a maximum about 14 DFA. After anthesis, reduced growth of unfertilized or defective ovaries was partly discriminated from successful fruit at 5 DFA and completely at 25 DFA. Time indices of RGR inflections were similar among cultivars when adjusted for anthesis date alone, until the end of pit growth. Asymptotic growth of the pit underpinned the declining growth rate of fruit at the end of the first exponential

  5. Seed dormancy and persistent sediment seed banks of ephemeral freshwater rock pools in the Australian monsoon tropics.

    Science.gov (United States)

    Cross, Adam T; Turner, Shane R; Renton, Michael; Baskin, Jerry M; Dixon, Kingsley W; Merritt, David J

    2015-04-01

    Rock pools are small, geologically stable freshwater ecosystems that are both hydrologically and biologically isolated. They harbour high levels of plant endemism and experience environmental unpredictability driven by the presence of water over variable temporal scales. This study examined the hypothesis that the sediment seed bank in monsoon tropical freshwater rock pools would persist through one or more periods of desiccation, with seed dormancy regulating germination timing in response to rock pool inundation and drying events. Seeds were collected from seven dominant rock pool species, and germination biology and seed dormancy were assessed under laboratory conditions in response to light, temperature and germination stimulators (gibberellic acid, karrikinolide and ethylene). Field surveys of seedling emergence from freshwater rock pools in the Kimberley region of Western Australia were undertaken, and sediment samples were collected from 41 vegetated rock pools. Seedling emergence and seed bank persistence in response to multiple wetting and drying cycles were determined. The sediment seed bank of individual rock pools was large (13 824 ± 307 to 218 320 ± 42 412 seeds m(-2) for the five species investigated) and spatially variable. Seedling density for these same species in the field ranged from 13 696 to 87 232 seedlings m(-2). Seeds of rock pool taxa were physiologically dormant, with germination promoted by after-ripening and exposure to ethylene or karrikinolide. Patterns of seedling emergence varied between species and were finely tuned to seasonal temperature and moisture conditions, with the proportions of emergent seedlings differing between species through multiple inundation events. A viable seed bank persisted after ten consecutive laboratory inundation events, and seeds retained viability in dry sediments for at least 3 years. The persistent seed bank in freshwater rock pools is likely to provide resilience to plant

  6. Phylogenetic Analysis, Lineage-Specific Expansion and Functional Divergence of seed dormancy 4-Like Genes in Plants.

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    Saminathan Subburaj

    Full Text Available The rice gene seed dormancy 4 (OsSdr4 functions in seed dormancy and is a major factor associated with pre-harvest sprouting (PHS. Although previous studies of this protein family were reported for rice and other species, knowledge of the evolution of genes homologous to OsSdr4 in plants remains inadequate. Fifty four Sdr4-like (hereafter designated Sdr4L genes were identified in nine plant lineages including 36 species. Phylogenetic analysis placed these genes in eight subfamilies (I-VIII. Genes from the same lineage clustered together, supported by analysis of conserved motifs and exon-intron patterns. Segmental duplications were present in both dicot and monocot clusters, while tandemly duplicated genes occurred only in monocot clusters indicating that both tandem and segmental duplications contributed to expansion of the grass I and II subfamilies. Estimation of the approximate ages of the duplication events indicated that ancestral Sdr4 genes evolved from a common angiosperm ancestor, about 160 million years ago (MYA. Moreover, diversification of Sdr4L genes in mono and dicot plants was mainly associated with genome-wide duplication and speciation events. Functional divergence was observed in all subfamily pairs, except IV/VIIIa. Further analysis indicated that functional constraints between subfamily pairs I/II, I/VIIIb, II/VI, II/VIIIb, II/IV, and VI/VIIIb were statistically significant. Site and branch-site model analyses of positive selection suggested that these genes were under strong adaptive selection pressure. Critical amino acids detected for both functional divergence and positive selection were mostly located in the loops, pointing to functional importance of these regions in this protein family. In addition, differential expression studies by transcriptome atlas of 11 Sdr4L genes showed that the duplicated genes may have undergone divergence in expression between plant species. Our findings showed that Sdr4L genes are

  7. Secretome within the bone marrow microenvironment: A basis for mesenchymal stem cell treatment and role in cancer dormancy.

    Science.gov (United States)

    Eltoukhy, Hussam S; Sinha, Garima; Moore, Caitlyn; Gergues, Marina; Rameshwar, Pranela

    2018-05-31

    The secretome produced by cells within the bone marrow is significant to homeostasis. The bone marrow, a well-studied organ, has multiple niches with distinct roles for supporting stem cell functions. Thus, an understanding of mediators involved in the regulation of stem cells could serve as a model for clinical problems and solutions such as tissue repair and regeneration. The exosome secretome of bone marrow stem cells is a developing area of research with respect to the regenerative potential by bone marrow cell, particularly the mesenchymal stem cells. The bone marrow niche regulates endogenous processes such as hematopoiesis but could also support the survival of tumors such as facilitating the cancer stem cells to exist in dormancy for decades. The bone marrow-derived secretome will be critical to future development of therapeutic strategies for oncologic diseases, in addition to regenerative medicine. This article discusses the importance for parallel studies to determine how the same secretome may compromise safety during the use of stem cells in regenerative medicine. Copyright © 2018 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  8. Effect of low dose {gamma} radiation on the dormancy breaking and physiological activity of 'Dejima' seed potato

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. S.; Kim, D. H.; Baek, M. H.; Lee, Y. K. [KAERI, Taejon (Korea, Republic of); Lee, Y. B. [Chungnam National Univ., Taejon (Korea, Republic of)

    2001-05-01

    To observe the stimulating effects of low dose {gamma}-radiation on the dormancy breaking and physiological activity, potato (Solanum tuberosum L. cv. Dejima) were irradiated at the dose of 0.5 {approx} 30 Gy. Low dose {gamma}-radiation had promoting effects on the srouting rate the optimum dose of 1 Gy and 2 Gy and on the sprout length at the optimum dose of 2 Gy and 4 Gy. In case of number of sprouts, there were increased in all of the low dose irradiation groups and period storages, which showed very significant promoting effects at 4,8,16 Gy of 15 DAP. The field growth of 45 DAP were increased at all of the low dose irradiation group, which particularly were very significant promoting effect at 4 Gy irradiation group. Irradiation didn't have significant effects on the antioxidant enzyme activity of potato plantlet, but the peroxidase activity of 45 DAP plantlet increased at 4 Gy irradiation group.

  9. Presowing treatments to breaking seed dormancy of Pterocarya stenoptera C. DC. as an indicator of potential invasiveness

    Directory of Open Access Journals (Sweden)

    Grbić Mihailo

    2011-01-01

    Full Text Available The Small-winged wingnut is a 12 to 20 metres tall, deciduous and fast growing tree with large substantial branches that spread as wide as the tree is tall. The 15 to 30 cm long winged fruit catkins, which turn brown in the autumn, are suspended below the branches. The species is not described by domestic authors in Serbia. The seed was introduced from Sofia (from the Arboretum of the Forestry University of Sofia, Bulgaria - Lesotehničeski universitet, Sofija, and subjected to classical stratification and naked stratification during the period of 1 and 2 months. Germination capacity varied among the treatments. The largest number of germinated seeds was observed in the shorter stratifications, (1 month the classical (56.5% and the naked (51.0% with no significant difference. The values of real germination of all treatments were between 69-88%. High value of RG, compared to GC, indicated that more than 40% of the seeds were empty. However, the results of the control as well as other parameters of seed germination clearly point to the fact that practically no deep embryo dormancy was observed, but the seed is recalcitrant and microbiotic. The results indicate a non-invasive character of the species in terms of reproductive potential.

  10. Influence of low dose {gamma} radiation on the dormancy, growth and physiological activity of seed potato (solanum tuberosum L.)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. S.; Lee, Y. K.; Lee, H. Y.; Baek, M. H.; Yoo, Z. C. [KAERI, Taejon (Korea, Republic of)

    2002-05-01

    To observe the stimulating effect of low dose {gamma} radiation on the dormancy breaking and growth of potato with different storage duration and conditions, potato were irradiated with the dose of 1 {approx} 16 Gy. Though varied with storage duration and conditions, sprouting rate of potato stored at 5 .deg. C in the dark was promoted at the 8 and 16 Gy irradiation group compared to 20 .deg. C in the light. The field growth of potato stored at 5 .deg. C in the dark was highly increased at the 2, 4, 8 Gy irradiation group. The CAT activity of potato was increased by about 20% at 1,8 and 16 Gy irradiation group. POD activity was also increased by 7 {approx} 16% at 1, 8 and 16 Gy irradiation group compared to the control. Fv/Fm was not changed by the low dose {gamma} radiation. However, the effective quantum yield of PSII was slightly increased by about 12% at 1 and 16 Gy irradiation group. Seedling irradiated with low dose {gamma} radiation showed the lower excitation pressure on PSII (1- {sub q}P), while NPQ was greatly increased by 45% at 4 Gy irradiation group. These results clearly showed the positive effect of low dose {gamma} radiation on the seedling growth of potato via increasing photoprotective capacities of photosynthetic apparatus.

  11. Structural characterization of annatto seeds (Bixa orellana) by transmission and scanning electron microscopy submitted to gamma radiation for dormancy break

    Energy Technology Data Exchange (ETDEWEB)

    Harder, Marcia N.C.; Nogueira, Neusa L.; Arthur, Valter; Rossi, Monica L.; Rodriguez, Adriana P.M. [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)]. E-mails: mnharder@cena.usp.br; nogueira@cena.usp.br; arthur@cena.usp.br; mnicalr@cena.usp.br; riana@cena.usp.br

    2007-07-01

    The annatto (Bixa orellana) is the only species of the Bixaceae family. From the seeds an important food colorant is obtained, bixin, for the industry and domestic use. More recently studies have focused more extensively in medicinal purpose of the species. Due to structural and physiologic characteristics, the seeds have low germination rate, around 30 %. The irradiation of seeds with gamma radiation can promote the increase and/or acceleration of germination, better plant development and productivity, among other aspects. The radiation doses used for this purpose should not cause genetic modifications in the organism, hence experimentation is needed to define the appropriate doses. Absence of research done annatto related to the use of the irradiation aiming at the increase of germination rates lead to the structural characterization of the annatto seeds submitted to gamma radiation through transmission (TEM) and scanning electron microscopy (SEM). The objective of this study was to verify the effect of radiation on the seeds structures during the process of dormancy break. Dry seeds and seeds immersed in distilled water for 24 hours were submitted to gamma radiation from source of Co{sup 60} type Gammacell-220 at CENA/USP, at doses 100 Gy. After irradiation the seeds were processed for TEM and SEM. Preliminary results, showed structural modifications in the seeds. (author)

  12. Response of soft winter wheat (Triticum aestivum L. to longtime enforced dormancy and time of spring vegetation recommencing

    Directory of Open Access Journals (Sweden)

    В. С. Хахула

    2013-05-01

    Full Text Available The article highlights the results of studying the soft winter wheat response to the duration of enforced winter dormancy and the time of vegetation recommencing, their impact on growth, development and the survival of the crops. It is found that the impact of those factors in the conditions of central Forest-Steppe of Ukraine is essential, which is to be taken into consideration when scheduling the measures of spring and summer care over the cultivated crops, in particular, where the spring extra nutrition takes place, pesticides and growth regulators are applied, the spaced planting resowing or partial resowing issues are to be settled down. The ecological effect of spring vegetation recommencing dates does not expose annually, therefore it is not always possible to predict the plant development type, but it is possible, nevertheless, to influence the processes of growth, development and survival of plants throughout spring-summer period and the development of their production capacity by means of introducing the intense technologies, optimization of mineral nutrition and the use of plant growth regulators, protection from rogues, diseases, pests.

  13. The effect of altitude on breaking seed dormancy and stimulation of seed germination of Persian hogweed (Heracleum persicum).

    Science.gov (United States)

    Salehani, M Khajavi; Mahmoudi, J; Mahdavi, S Kh; Habibzadeh, R

    2013-01-01

    Persian hogweed is a perennial herb and aromatic plant which has pharmaceutical and fodder values, and the main propagation method of this species is seed. The goal of this study was to investigate the effect of altitude on breaking dormancy and stimulate seed germination of this species. The study was designed and carried out using the test of seed analysis. For our purpose, seeds were collected from three different altitudes (1700, 2200, 2700 masl) in Kojoor area. After initial purification, germination percent (GP) and speed (GS) of each elevation were determined by cold stratification compared to control. According to results, control seeds did not germinate, showing that the seeds of this species need to be treated. Statistical analysis of results showed that there are significant differences between GP and GS of each elevation, as seeds of higher elevation had slower and less germination in longer periods. So, changes in elevation are an effective factor on seed germination characteristics of this species and this factor has to be considered in seed preparation and restoration with this species.

  14. Seed dormancy responses to temperature relate to Nothofagus species distribution and determine temporal patterns of germination across altitudes in Patagonia.

    Science.gov (United States)

    Arana, María V; Gonzalez-Polo, Marina; Martinez-Meier, Alejandro; Gallo, Leonardo A; Benech-Arnold, Roberto L; Sánchez, Rodolfo A; Batlla, Diego

    2016-01-01

    Seeds integrate environmental cues that modulate their dormancy and germination. Although many mechanisms have been identified in laboratory experiments, their contribution to germination dynamics in existing communities and their involvement in defining species habitats remain elusive. By coupling mathematical models with ecological data we investigated the contribution of seed temperature responses to the dynamics of germination of three Nothofagus species that are sharply distributed across different altitudes in the Patagonian Andes. Seed responsiveness to temperature of the three Nothofagus species was linked to the thermal characteristics of their preferred ecological niche. In their natural distribution range, there was overlap in the timing of germination of the species, which was restricted to mid-spring. By contrast, outside their species distribution range, germination was temporally uncoupled with altitude. This phenomenon was described mathematically by the interplay between interspecific differences in seed population thermal parameters and the range in soil thermic environments across different altitudes. The observed interspecific variations in seed responsiveness to temperature and its environmental regulation, constitute a major determinant of the dynamics of Nothofagus germination across elevations. This phenomenon likely contributes to the maintenance of patterns of species abundance across altitude by placing germinated seeds in a favorable environment for plant growth. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  15. Influence of low dose γ radiation on the dormancy, growth and physiological activity of seed potato (solanum tuberosum L.)

    International Nuclear Information System (INIS)

    Kim, J. S.; Lee, Y. K.; Lee, H. Y.; Baek, M. H.; Yoo, Z. C.

    2002-01-01

    To observe the stimulating effect of low dose γ radiation on the dormancy breaking and growth of potato with different storage duration and conditions, potato were irradiated with the dose of 1 ∼ 16 Gy. Though varied with storage duration and conditions, sprouting rate of potato stored at 5 .deg. C in the dark was promoted at the 8 and 16 Gy irradiation group compared to 20 .deg. C in the light. The field growth of potato stored at 5 .deg. C in the dark was highly increased at the 2, 4, 8 Gy irradiation group. The CAT activity of potato was increased by about 20% at 1,8 and 16 Gy irradiation group. POD activity was also increased by 7 ∼ 16% at 1, 8 and 16 Gy irradiation group compared to the control. Fv/Fm was not changed by the low dose γ radiation. However, the effective quantum yield of PSII was slightly increased by about 12% at 1 and 16 Gy irradiation group. Seedling irradiated with low dose γ radiation showed the lower excitation pressure on PSII (1- q P), while NPQ was greatly increased by 45% at 4 Gy irradiation group. These results clearly showed the positive effect of low dose γ radiation on the seedling growth of potato via increasing photoprotective capacities of photosynthetic apparatus

  16. The Roles of the Bone Marrow Microenvironment in Controlling Tumor Dormancy

    Science.gov (United States)

    2016-10-01

    indicated, scaffolds were further modified by water annealing at room temperature for 8 h to induce b-sheets [23]. 2.2. In vivo scaffold implantation...peritoneum. 4. Exteriorize and gently stabilize the prostate dorsal lobes with a wet (1 PBS) cotton swab (Figure 7). Figure 6 Anatomy of murine tail

  17. The Roles of the Bone Marrow Microenvironment in Controlling Tumor Dormancy

    Science.gov (United States)

    2017-10-01

    commonly metastasizes to bone with consequent bone pain , pathological fractures, ver- tebrae compressions, and hypercalcemia, this process is...treat potential progression of hepatitis C-related fibrosis reduced circulating TGF-beta and IL-6.92 Abdominal pain , rash, and nausea were seen in a...jpi.12380. 240. Pariente R, Pariente JA, Rodríguez AB, Espino J. Melatonin sensitizes human cervical cancer HeLa cells to cisplatin-induced

  18. Superação de dormência em sementes de Butia capitata Overcoming dormancy in seeds of Butia capitata

    Directory of Open Access Journals (Sweden)

    Claudimar Sidnei Fior

    2011-07-01

    Full Text Available Com o objetivo de identificar métodos eficientes para a superação da dormência de sementes de B. capitata (Mart. Becc. semeadas in vitro e em germinador, foram conduzidos testes com escarificação mecânica em pré-semeadura, através da abertura parcial ou total da cavidade embrionária de sementes isoladas dos endocarpos. A abertura da cavidade embrionária acelerou significativamente a germinação, principalmente quando houve retirada total do opérculo da semente, permitindo a germinação de, em média, 90% dos embriões, independentemente da procedência dos acessos. A dormência das sementes de B. capitata parece estar relacionada com a barreira mecânica imposta pelos tecidos da semente que dificultam o desenvolvimento do embrião, o que sugere dormência exógena mecânica.Aiming to identify efficient conditions to break dormancy in Butia capitata (Mart. Becc. seeds sown in vitro and in an incubator tests were conducted with mechanical scarification in pre-sowing, by partial or total opening of the seed embryonic cavity, isolated of the endocarps. The embryonic cavity opening accelerated germination significantly, especially when there was total removal of the seed cap, allowing germination on average 90% of embryos, regardless of the provenance of the accessions. The seed dormancy of B. capitata seems to be related to the mechanical barrier imposed by the seed tissues that hamper the embryo development, suggesting mechanical exogenous dormancy.

  19. Overexpression of Adenylyl Cyclase Encoded by the Mycobacterium tuberculosis Rv2212 Gene Confers Improved Fitness, Accelerated Recovery from Dormancy and Enhanced Virulence in Mice

    Directory of Open Access Journals (Sweden)

    Margarita O. Shleeva

    2017-08-01

    Full Text Available Earlier we demonstrated that the adenylyl cyclase (AC encoded by the MSMEG_4279 gene plays a key role in the resuscitation and growth of dormant Mycobacterium smegmatis and that overexpression of this gene leads to an increase in intracellular cAMP concentration and prevents the transition of M. smegmatis from active growth to dormancy in an extended stationary phase accompanied by medium acidification. We surmised that the homologous Rv2212 gene of M. tuberculosis (Mtb, the main cAMP producer, plays similar physiological roles by supporting, under these conditions, the active state and reactivation of dormant bacteria. To test this hypothesis, we established Mtb strain overexpressing Rv2212 and compared its in vitro and in vivo growth characteristics with a control strain. In vitro, the AC-overexpressing pMindRv2212 strain demonstrated faster growth in a liquid medium, prolonged capacity to form CFUs and a significant delay or even prevention of transition toward dormancy. AC-overexpressing cells exhibited easier recovery from dormancy. In vivo, AC-overexpressing bacteria demonstrated significantly higher growth rates (virulence in the lungs and spleens of infected mice compared to the control strain, and, unlike the latter, killed mice in the TB-resistant strain before month 8 of infection. Even in the absence of selecting hygromycin B, all pMindRv2212 CFUs retained the Rv2212 insert during in vivo growth, strongly suggesting that AC overexpression is beneficial for bacteria. Taken together, our results indicate that cAMP supports the maintenance of Mtb cells vitality under unfavorable conditions in vitro and their virulence in vivo.

  20. Mycobacterium tuberculosis septum site determining protein, Ssd encoded by rv3660c, promotes filamentation and elicits an alternative metabolic and dormancy stress response

    Directory of Open Access Journals (Sweden)

    Crew Rebecca

    2011-04-01

    Full Text Available Abstract Background Proteins that are involved in regulation of cell division and cell cycle progression remain undefined in Mycobacterium tuberculosis. In addition, there is a growing appreciation that regulation of cell replication at the point of division is important in establishing a non-replicating persistent state. Accordingly, the objective of this study was to use a systematic approach consisting of consensus-modeling bioinformatics, ultrastructural analysis, and transcriptional mapping to identify septum regulatory proteins that participate in adaptive metabolic responses in M. tuberculosis. Results Septum site determining protein (Ssd, encoded by rv3660c was discovered to be an ortholog of septum site regulating proteins in actinobacteria by bioinformatics analysis. Increased expression of ssd in M. smegmatis and M. tuberculosis inhibited septum formation resulting in elongated cells devoid of septa. Transcriptional mapping in M. tuberculosis showed that increased ssd expression elicited a unique response including the dormancy regulon and alternative sigma factors that are thought to play a role in adaptive metabolism. Disruption of rv3660c by transposon insertion negated the unique transcriptional response and led to a reduced bacterial length. Conclusions This study establishes the first connection between a septum regulatory protein and induction of alternative metabolism consisting of alternative sigma factors and the dormancy regulon that is associated with establishing a non-replicating persistent intracellular lifestyle. The identification of a regulatory component involved in cell cycle regulation linked to the dormancy response, whether directly or indirectly, provides a foundation for additional studies and furthers our understanding of the complex mechanisms involved in establishing a non-replicating state and resumption of growth.

  1. In vitro embryo culture of rarely endangered musella lasiocarpa (musaceae) with embryo dormancy

    International Nuclear Information System (INIS)

    Anjun, T.

    2014-01-01

    Musella lasiocarpa (Musaceae) is an ornamental annually producing many viable seeds, but seldom recruited by seeds in the wild. One mature Musella seed has a small mushroom-shaped embryo without discernible organ differentiation. Therefore, freshly-harvested mature seeds are dormant. When the seeds gradually finished differentiation during warm stratification at 23 degree C, they germinated to 82%. Besides, extracted embryos from fresh seeds did not germinate on the basal medium of Murshige and Skoog medium (MS) supplemented with 3% sucrose and 0.8% agar, but they were induced to form calli and root by media. The optimum medium for inducing calli was MS + 1.0 mg/L 6-BA + 0.05 mg/L NAA + 100 mg/L Vc with the highest proliferation coefficient (7.3) in 35 days. Moreover, the embryos from the 6-month warm stratified seeds could proliferate on the suitable medium. The optimal medium for rooting was MS + 0.5 mg/L 2, 4-D + Vitamin C 100 mg/L. The results confirmed that both the embryo developmental stage and appropriate combination of chemicals significantly affected seed germination and In vitro embryo culture of this species. (author)

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

    Czech Academy of Sciences Publication Activity Database

    Graeber, K.; Linkies, A.; Steinbrecher, T.; Tarkowská, Danuše; Turečková, Veronika; Ignatz, M.; Voegele, A.; Urbanová, Terezie; Strnad, Miroslav; Leubner-Metzger, Gerhard

    2014-01-01

    Roč. 111, č. 34 (2014), E3571-E3580 ISSN 0027-8424 R&D Projects: GA ČR GD522/08/H003; GA MŠk LK21306; GA MŠk(CZ) LO1204; GA ČR GA14-34792S Grant - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional support: RVO:61389030 Keywords : dormancy gene DOG1 * gibberellin metabolism * germination temperature Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.674, year: 2014

  3. Comparative Mapping of Seed Dormancy Loci Between Tropical and Temperate Ecotypes of Weedy Rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Lihua Zhang

    2017-08-01

    Full Text Available Genotypic variation at multiple loci for seed dormancy (SD contributes to plant adaptation to diverse ecosystems. Weedy rice (Oryza sativa was used as a model to address the similarity of SD genes between distinct ecotypes. A total of 12 quantitative trait loci (QTL for SD were identified in one primary and two advanced backcross (BC populations derived from a temperate ecotype of weedy rice (34.3°N Lat.. Nine (75% of the 12 loci were mapped to the same positions as those identified from a tropical ecotype of weedy rice (7.1°N Lat.. The high similarity suggested that the majority of SD genes were conserved during the ecotype differentiation. These common loci are largely those collocated/linked with the awn, hull color, pericarp color, or plant height loci. Phenotypic correlations observed in the populations support the notion that indirect selections for the wild-type morphological characteristics, together with direct selections for germination time, were major factors influencing allelic distributions of SD genes across ecotypes. Indirect selections for crop-mimic traits (e.g., plant height and flowering time could also alter allelic frequencies for some SD genes in agroecosystems. In addition, 3 of the 12 loci were collocated with segregation distortion loci, indicating that some gametophyte development genes could also influence the genetic equilibria of SD loci in hybrid populations. The SD genes with a major effect on germination across ecotypes could be used as silencing targets to develop transgene mitigation (TM strategies to reduce the risk of gene flow from genetically modified crops into weed/wild relatives.

  4. Changes in autumn vegetation dormancy onset date and the climate controls across temperate ecosystems in China from 1982 to 2010.

    Science.gov (United States)

    Yang, Yuting; Guan, Huade; Shen, Miaogen; Liang, Wei; Jiang, Lei

    2015-02-01

    Vegetation phenology is a sensitive indicator of the dynamic response of terrestrial ecosystems to climate change. In this study, the spatiotemporal pattern of vegetation dormancy onset date (DOD) and its climate controls over temperate China were examined by analysing the satellite-derived normalized difference vegetation index and concurrent climate data from 1982 to 2010. Results show that preseason (May through October) air temperature is the primary climatic control of the DOD spatial pattern across temperate China, whereas preseason cumulative precipitation is dominantly associated with the DOD spatial pattern in relatively cold regions. Temporally, the average DOD over China's temperate ecosystems has delayed by 0.13 days per year during the past three decades. However, the delay trends are not continuous throughout the 29-year period. The DOD experienced the largest delay during the 1980s, but the delay trend slowed down or even reversed during the 1990s and 2000s. Our results also show that interannual variations in DOD are most significantly related with preseason mean temperature in most ecosystems, except for the desert ecosystem for which the variations in DOD are mainly regulated by preseason cumulative precipitation. Moreover, temperature also determines the spatial pattern of temperature sensitivity of DOD, which became significantly lower as temperature increased. On the other hand, the temperature sensitivity of DOD increases with increasing precipitation, especially in relatively dry areas (e.g. temperate grassland). This finding stresses the importance of hydrological control on the response of autumn phenology to changes in temperature, which must be accounted in current temperature-driven phenological models. © 2014 John Wiley & Sons Ltd.

  5. 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.

  6. Seed dormancy is modulated in recently evolved chlorsulfuron-resistant Turkish biotypes of wild mustard (Sinapis arvensis

    Directory of Open Access Journals (Sweden)

    Muhamet eTopuz

    2015-07-01

    Full Text Available Biotypes of the broad-leaved wild mustard (Sinapis arvensis L. found in wheat fields of Aegean and Marmara region of Turkey were characterized and shown to have developed resistance to sulfonylurea (chlorsulfuron, an inhibitor of acetolactate synthase (ALS. DNA sequence analysis of the ALS genes from two such resistant (‘R’ biotypes, KNF-R1 and KNF-R2, revealed point mutations, CCT (Pro 197 to TCT (Ser 197 in KNF-R1 and CCT (Pro 197 to ACT (Thr 197 in KNF-R2; these substitutions are consistent with the presence of chlorsulfuron-insensitive ALS enzyme activity in the ‘R’ S. arvensis biotypes. An additional phenotype of chlorsulfuron resistance in the Turkish S. arvensis ‘R’ biotypes was revealed in the form of an altered seed dormancy behavior over 4 to 48 months of dry storage (after-ripening compared to the susceptible (‘S’ biotypes. Seeds of the ‘S’ biotypes dry stored for 4 months had a higher initial germination, which sharply decreased with storage time, while the seeds of the ‘R’ biotypes had lower germination after 4-months storage, rising sharply and peaking thereafter by 24 months’ of dry storage. The ‘R’ biotype seeds continued to maintain a higher germination percentage even after 48 months of after-ripening. The seed weight of ‘R’ and ‘S’ biotypes after-ripened for 4 months was similar but those after-ripened for 48 months differed, ‘R’ seeds were significantly heavier than those of the ‘S’ seeds. Differential seed germinability between ‘S’ and ‘R’ biotypes was found not a case of differential viability, temperature regimen or non-response to pro-germination hormone GA3. These studies are of relevance to ecological fitness of herbicide-resistant biotypes in terms of seed viability and germination.

  7. Fruit size and sampling sites affect on dormancy, viability and germination of teak (Tectona grandis L.) seeds

    International Nuclear Information System (INIS)

    Akram, M.; Aftab, F.

    2016-01-01

    In the present study, fruits (drupes) were collected from Changa Manga Forest Plus Trees (CMF-PT), Changa Manga Forest Teak Stand (CMF-TS) and Punjab University Botanical Gardens (PUBG) and categorized into very large (= 17 mm dia.), large (12-16 mm dia.), medium (9-11 mm dia.) or small (6-8 mm dia.) fruit size grades. Fresh water as well as mechanical scarification and stratification were tested for breaking seed dormancy. Viability status of seeds was estimated by cutting test, X-rays and In vitro seed germination. Out of 2595 fruits from CMF-PT, 500 fruits were of very large grade. This fruit category also had highest individual fruit weight (0.58 g) with more number of 4-seeded fruits (5.29 percent) and fair germination potential (35.32 percent). Generally, most of the fruits were 1-seeded irrespective of size grades and sampling sites. Fresh water scarification had strong effect on germination (44.30 percent) as compared to mechanical scarification and cold stratification after 40 days of sowing. Similarly, sampling sites and fruit size grades also had significant influence on germination. Highest germination (82.33 percent) was obtained on MS (Murashige and Skoog) agar-solidified medium as compared to Woody Plant Medium (WPM) (69.22 percent). Seedlings from all the media were transferred to ex vitro conditions in the greenhouse and achieved highest survival (28.6 percent) from seedlings previously raised on MS agar-solidified medium after 40 days. There was an association between the studied parameters of teak seeds and the sampling sites and fruit size. (author)

  8. Seed dormancy is modulated in recently evolved chlorsulfuron-resistant Turkish biotypes of wild mustard (Sinapis arvensis)

    Science.gov (United States)

    Topuz, Muhamet; Nemli, Yildiz; Fatima, Tahira; Mattoo, Autar

    2015-07-01

    Biotypes of the broad-leaved wild mustard (Sinapis arvensis L.) found in wheat fields of Aegean and Marmara region of Turkey were characterized and shown to have developed resistance to sulfonylurea (chlorsulfuron), an inhibitor of acetolactate synthase (ALS). DNA sequence analysis of the ALS genes from two such resistant (‘R’) biotypes, KNF-R1 and KNF-R2, revealed point mutations, CCT (Pro 197) to TCT (Ser 197) in KNF-R1 and CCT (Pro 197) to ACT (Thr 197) in KNF-R2; these substitutions are consistent with the presence of chlorsulfuron-insensitive ALS enzyme activity in the ‘R’ S. arvensis biotypes. An additional phenotype of chlorsulfuron resistance in the Turkish S. arvensis ‘R’ biotypes was revealed in the form of an altered seed dormancy behavior over 4 to 48 months of dry storage (after-ripening) compared to the susceptible (‘S’) biotypes. Seeds of the ‘S’ biotypes dry stored for 4 months had a higher initial germination, which sharply decreased with storage time, while the seeds of the ‘R’ biotypes had lower germination after 4-months storage, rising sharply and peaking thereafter by 24 months’ of dry storage. The ‘R’ biotype seeds continued to maintain a higher germination percentage even after 48 months of after-ripening. The seed weight of ‘R’ and ‘S’ biotypes after-ripened for 4 months was similar but those after-ripened for 48 months differed, ‘R’ seeds were significantly heavier than those of the ‘S’ seeds. Differential seed germinability between ‘S’ and ‘R’ biotypes was found not a case of differential viability, temperature regimen or non-response to pro-germination hormone GA3. These studies are of relevance to ecological fitness of herbicide-resistant biotypes in terms of seed viability and germination.

  9. Effect of visible light on progressive dormancy of Escherichia coli cells during the survival process in natural fresh water

    International Nuclear Information System (INIS)

    Barcina, I.; Gonzalez, J.M.; Iriberri, J.; Egea, L.

    1989-01-01

    Some effects of visible light on the survival of Escherichia coli in waters of the Butron river were studied by comparing illuminated and nonilluminated systems. The following count methods were used: CFU on a selective medium (eosin-methylene blue agar), CFU on a medium of recuperation (Trypticase soy agar with yeast extract and glucose), number of metabolically active cells by reduction of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride (INT) to INT-formazan, and total number of E. coli cells as determined by the acridine orange direct-count method. In the illuminated systems, decreases in CFU of E. coli and in the number of metabolically active cells were observed. However, no decline of the total number of E. coli cells was observed. By count methods, different stages of progressive dormancy of E. coli cells were determined to exist in illuminated systems. Culturable and recoverable cells were defined as viable cells, and metabolically active cells and morphologically intact cells were defined as somnicells. Indirect activity measurements were also done by using [14C]glucose. In illuminated systems, a decrease of glucose uptake by E. coli cells was observed throughout the experiments. The assimilated fraction of [14C]glucose decreased faster than the respired fraction in illuminated systems. The percentage of respired [14C]glucose (14CO2 production) with respect to the total glucose uptake increased throughout the experiments, and the percentage of assimilated glucose decreased. Therefore, the visible light was also responsible for an additional inhibition of biosynthetic processes

  10. Dormancy in Deinococcus sp. UDEC-P1 as a survival strategy to escape from deleterious effects of carbon starvation and temperature.

    Science.gov (United States)

    Guerra, Matías; González, Karina; González, Carlos; Parra, Boris; Martínez, Miguel

    2015-09-01

    Dormancy is characterized by low metabolism and absence of protein synthesis and cellular division enabling bacterial cells to survive under stress. The aim was to determine if carbon starvation and low temperature are factors that modify the proportion of dormant/active cells in Deinococcus sp. UDEC-P1. By flow cytometry, RedoxSensor Green (RSG) was used to quantify metabolic activity and Propidium Iodide (PI) to evaluate membrane integrity in order to determine the percentage of dormant cells. Cell size and morphology were determined using scanning electronic microscopy. Under carbon starvation at 30°C, Deinococcus sp. UDEC-P1 increased its proportion of dormant cells from 0.1% to 20%, decreased the count of culturable cells and average cell volume decreased 7.1 times. At 4°C, however, the proportion of dormant cells increased only to 6%, without a change in the count of culturable cells and an average cellular volume decrease of 4.1 times and 3% of the dormant cells were able to be awakened. Results indicate a greater proportion of dormant Deinococcus sp. UDEC-P1 cells at 30ºC and it suggests that carbon starvation is more deleterious condition at 30ºC than 4ºC. For this reason Deinococcus sp. UDEC-P1 cells are more likely to enter into dormancy at higher temperature as a strategy to survive. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  11. Study of Dormancy Type and Effect of Different Pre-Sowing Treatments on Seed Germination of Bladder-Senna (Colutea bohsei Boiss. in Laboratory Conditions

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    Ahmad BEIKMOHAMMADI

    2012-05-01

    Full Text Available The present study was conducted in order to evaluate the existence and type of the dormancy and effects of different dormancy breaking treatments on seed germination of Colutea buhsei Boiss. (Fabaceae as one of the Iran native plants, arid-land and ornamental shrub with ability of usage in the urban landscape design. The experiment was performed with 15 treatments and 3 replications in a completely randomized design. Seeds were subjected to different treatments including various levels of GA3, concentrated (98% H2SO4, cold stratification (CS, soaking with tab water, floating in hot water (100�C followed by continual cooling for 24 hr in the same water and combined treatments. Afterwards seeds were sown in laboratory conditions to determine the factors� effects on germination percentage (GP, germination rate (GR, root and shoot length of Colutea bohsei seeds. All of these treatments, except for GA3 (250 and 500 ppm, increased the percentage and rate of the seed germination. Maximum germination percentage (66.25% and rate (14.9 seeds per day in 7 days was obtained at concentrated (98% H2SO4 (15 min. Maximum root and shoot length was observed at concentrated (98% H2SO4 (15 min plus GA3 (100 ppm, 24 hr. Use of GA3 (100 ppm in 24 hr after H2SO4 increased the germination rate and shoot length but this additive effect was not significant.

  12. Effects of chemical treatments and environmental factors on seed dormancy and germination of shepherd's purse (Capsella bursa-pastoris (L. Medic.

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    Mohammad Rezvani

    2014-12-01

    Full Text Available Shepherd's purse (Capsella bursa-pastoris is a problematic weed in citrus orchards and crop fields in northern Iran. In a series of laboratory and greenhouse experiments, we evaluated the effects that treatment with gibberellic acid (GA3 and potassium nitrate (KNO3, as well as environmental factors, including temperature, the duration of pre-chilling (wet and dry, drought stress, salt stress, pH, and sowing depth, have on seed dormancy breaking and germination in C. bursa-pastoris. Treatment with GA3 strongly stimulated germination of C. bursa-pastoris in conditions of light/dark and continuous darkness. The germination rate was highest (40.08% for seeds treated with 400 ppm of GA3 in the light/dark condition. Treatment with KNO3 did not significantly influence seed germination. Longer wet pre-chilling promoted germination and was more successful in seed dormancy breaking than was dry pre-chilling. Seed germination occurred at 10-30ºC and within a range of pH of 3-11. Drought and salt stress both strongly inhibited germination. Seedling emergence decreased in proportion to sowing depth. The rates of C. bursa-pastoris germination and seedling emergence were highest for seeds on the soil surface.

  13. Rain-induced spring wheat harvest losses

    Science.gov (United States)

    Bauer, A.; Black, A. L. (Principal Investigator)

    1983-01-01

    When rain or a combination of rain and high humidity delay wheat harvest, losses can occur in grain yield and/or grain quality. Yield losses can result from shattering, from reduction in test weight, and in the case of windrowed grain, from rooting of sprouting grain at the soil: windrow contact. Losses in grain quality can result from reduction in test weight and from sprouting. Sprouting causes a degradation of grain proteins and starches, hence flour quality is reduced, and the grain price deteriorates to the value of feed grain. Although losses in grain yield and quality are rain-induced, these losses do not necessarily occur because a standing or windrowed crop is wetted by rain. Spike water concentration in hard red spring wheat must be increased to about 45-49% before sprouting is initiated in grain that has overcome dormancy. The time required to overcome this dormancy after the cultivar has dried to 12 to 14% water concentration differs with hard red spring cultivars. The effect of rain on threshing-ready standing and windrowed hard red spring wheat grain yeild and quality was evaluated. A goal was to develop the capability to forecast the extent of expected loss of grain yield and quality from specific climatic events that delay threshing.

  14. The wheat Phs-A1 pre-harvest sprouting resistance locus delays the rate of seed dormancy loss and maps 0.3 cM distal to the PM19 genes in UK germplasm

    Czech Academy of Sciences Publication Activity Database

    Shorinola, O.; Bird, N.; Simmonds, J.; Berry, S.; Henriksson, T.; Jack, P.; Werner, P.; Gerjets, T.; Scholefield, D.; Balcárková, Barbora; Valárik, Miroslav; Holdsworth, M.J.; Flintham, J.; Uauy, C.

    2016-01-01

    Roč. 67, č. 14 (2016), s. 4169-4178 ISSN 0022-0957 R&D Projects: GA MŠk(CZ) LO1204; GA ČR(CZ) GA14-07164S Institutional support: RVO:61389030 Keywords : After-ripening * dormancy * PM19 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.830, year: 2016

  15. Breast and other cancer dormancy as a therapeutic endpoint: speculative recombinant T cell receptor ligand (RTL) adjuvant therapy worth considering?

    International Nuclear Information System (INIS)

    Bakács, Tibor; Mehrishi, Jitendra N

    2010-01-01

    Most individuals who died of trauma were found to harbour microscopic primary cancers at autopsies. Surgical excision of the primary tumour, unfortunately, seems to disturb tumour dormancy in over half of all metastatic relapses. A recently developed immune model suggested that the evolutionary pressure driving the creation of a T cell receptor repertoire was primarily the homeostatic surveillance of the genome. The model is based on the homeostatic role of T cells, suggesting that molecular complementarity between the positively selected T cell receptors and the self peptide-presenting major histocompatibility complex molecules establishes and regulates homeostasis, strictly limiting variations of its components. The repertoire is maintained by continuous peripheral stimulation via soluble forms of self-peptide-presenting major histocompatibility complex molecules governed by the law of mass action. The model states that foreign peptides inhibit the complementary interactions between the major histocompatibility complexes and T cell receptors. Since the vast majority of clinically detected cancers present self-peptides the model assumes that tumour cells are, paradoxically, under homeostatic T cell control. The novelty of our hypothesis therefore is that resection of the primary tumour mass is perceived as loss of 'normal' tissue cells. Consequently, T cells striving to reconstitute homeostasis stimulate rather than inhibit the growth of dormant tumour cells and avascular micrometastases. Here we suggest that such kick-start growths could be prevented by a recombinant T cell receptor ligand therapy that modifies T cell behaviour through a partial activation mechanism. The homeostatic T cell regulation of tumours can be tested in a tri-transgenic mice model engineered to express potent oncogenes in a doxycycline-dependent manner. We suggest seeding dissociated, untransformed mammary cells from doxycycline naïve mice into the lungs of two mice groups: one

  16. Effects of dormancy progression and low-temperature response on changes in the sorbitol concentration in xylem sap of Japanese pear during winter season.

    Science.gov (United States)

    Ito, Akiko; Sugiura, Toshihiko; Sakamoto, Daisuke; Moriguchi, Takaya

    2013-04-01

    In order to elucidate which physiological event(s) are involved in the seasonal changes of carbohydrate dynamics during winter, we examined the effects of different low temperatures on the carbohydrate concentrations of Japanese pear (Pyrus pyrifolia (Burm.) Nakai). For four winter seasons, large increases in the sorbitol concentration of shoot xylem sap occurred during mid- to late December, possibly due to the endodormancy completion and low-temperature responses. When trees were kept at 15 °C from 3 November to 3 December in order to postpone the initiation and completion of chilling accumulation that would break endodormancy, sorbitol accumulation in xylem sap was always higher from trees with sufficient chilling accumulation than from trees that received insufficient chilling. However, an additional increase in xylem sap sorbitol occurred around late December in trees regardless of whether their chilling accumulation naturally progressed or was postponed. To examine different temperature effects more closely, we compared the carbohydrate concentrations of trees subjected to either 6 or 0 °C treatment. The sorbitol concentration in xylem sap tremendously increased at 0 °C treatment compared with 6 °C treatment. However, an additional increase in xylem sap sorbitol occurred at both the temperatures when sufficient chilling accumulated with a peak coinciding with the peak expression in shoots of the sorbitol transporter gene (PpSOT2). Interestingly, the total carbohydrate concentration of shoots tremendously increased with exposure to 0 °C compared with exposure to 6 °C, but was not affected by the amount of accumulated chilling. Instead, as chilling accumulated the ratio of sorbitol to total soluble sugars in shoots increased. We presumed that carbohydrates in the shoot tissues may be converted to sorbitol and loaded into the xylem sap so that the sorbitol accumulation patterns were synchronized with the progression of dormancy, whereas the total

  17. The effects of free amino acids profiles on seeds germination/dormancy and seedlings development of two genetically different cultivars of Yemeni Pomegranates

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    Alhadi Fatima A.

    2012-04-01

    Full Text Available Plant seeds used rely on a wide range of internal mechanisms and physio-chemical factors to ensure their germination under favorable environmental conditions. Most plant seeds have complex process of germination, including water, oxygen, temperature availability, genome-wide gene expression, signal transduction, hormones stimulations, inhibitors removal and catalytic protein synthesis. In addition, influences of seeds nutrient values such as, protein, lipids, sugars and free amino acids have a special importance. Regarding, seeds free amino acids. Discussion of these individual factors needs to be put in context of their role in germination processes. Regarding, free amino acids seed storage, there is limited information about their relevant functions in activation and/or deactivation of required metabolic mechanisms and interactive compounds involved in this process in commercial plant cultivars. Therefore, current study was aimed to determine the probable influence of free amino acid compositions of seeds on germination process of two different (Punica granatum L. pomegranate cultivars including wild type Automi cultivar and edible Khazemi cultivar. In particular, we focused on the impact of amino acids contents variations on germination process and associated AAs compositional changes during various stages of germination and seedlings establishment. Amino acid analysis using HPLC detected all the essential and non-essential amino acids in the raw seeds of the studied cultivars, Automi and Khazemi along with AAs compositional changes occurred during different stages of seed germination. These AAs have been extensively analyzed in the context of their role in dormancy breaking capacities in plants species. Automi raw seeds are rich in Phe, that, is strongly related to ABA synthesis and hence might be responsible for the dormancy of Automi seeds, Khazemi raw seeds have sufficient levels of Arg, Glu and Met that have been reported to enhance

  18. A Combined Comparative Transcriptomic, Metabolomic, and Anatomical Analyses of Two Key Domestication Traits: Pod Dehiscence and Seed Dormancy in Pea (Pisum sp.

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    Petr Smýkal

    2017-04-01

    Full Text Available The origin of the agriculture was one of the turning points in human history, and a central part of this was the evolution of new plant forms, domesticated crops. Seed dispersal and germination are two key traits which have been selected to facilitate cultivation and harvesting of crops. The objective of this study was to analyze anatomical structure of seed coat and pod, identify metabolic compounds associated with water-impermeable seed coat and differentially expressed genes involved in pea seed dormancy and pod dehiscence. Comparative anatomical, metabolomics, and transcriptomic analyses were carried out on wild dormant, dehiscent Pisum elatius (JI64, VIR320 and cultivated, indehiscent Pisum sativum non-dormant (JI92, Cameor and recombinant inbred lines (RILs. Considerable differences were found in texture of testa surface, length of macrosclereids, and seed coat thickness. Histochemical and biochemical analyses indicated genotype related variation in composition and heterogeneity of seed coat cell walls within macrosclereids. Liquid chromatography–electrospray ionization/mass spectrometry and Laser desorption/ionization–mass spectrometry of separated seed coats revealed significantly higher contents of proanthocyanidins (dimer and trimer of gallocatechin, quercetin, and myricetin rhamnosides and hydroxylated fatty acids in dormant compared to non-dormant genotypes. Bulk Segregant Analysis coupled to high throughput RNA sequencing resulted in identification of 770 and 148 differentially expressed genes between dormant and non-dormant seeds or dehiscent and indehiscent pods, respectively. The expression of 14 selected dormancy-related genes was studied by qRT-PCR. Of these, expression pattern of four genes: porin (MACE-S082, peroxisomal membrane PEX14-like protein (MACE-S108, 4-coumarate CoA ligase (MACE-S131, and UDP-glucosyl transferase (MACE-S139 was in agreement in all four genotypes with Massive analysis of cDNA Ends (MACE data. In

  19. Condições de armazenamento na viabilidade e dormência de sementes de videira Effect of storage conditions on the viability and dormancy of grape seeds

    Directory of Open Access Journals (Sweden)

    Jocely Andreuccetti Maeda

    1985-01-01

    Full Text Available A manutenção da viabilidade de sementes por períodos mais ou menos longos está bastante relacionada com as condições em que elas são armazenadas. Temperatura e teor de umidade estão entre os fatores que mais afetam sua longevidade. O objetivo deste trabalho é o estudo da viabilidade e dormência de uva do cultivar Patrícia, armazenada durante 24 meses em dois tipos de recipientes - em vidro hermético e saco de papel - a temperaturas de 10, 20 e 30°C, com dois diferentes teores iniciais de umidade. A porcentagem de sementes dormentes e viáveis foi determinada bimestralmente durante os primeiros 12 meses, e semestralmente nos períodos mais longos. O armazenamento não quebrou a dormência das sementes de uva em nenhuma das condições estudadas. Enquanto as sementes frescas mostraram melhor conservação a 10°C quando embaladas em vidro hermético, sementes secas se conservaram melhor a 20°C. Em saco de papel, foram poucas as diferenças encontradas entre os tratamentos, a não ser nos períodos finais do armazenamento, quando 20°C se mostrou a pior temperatura de conservação. Dessa maneira, a dormência não foi alterada pelo armazenamento, nas condições estudadas, e a viabilidade foi bastante afetada tanto pelo tipo de embalagem como pela temperatura de armazenamento.Longevity of seeds is affected by the storage conditions, being temperature and seed moisture content the major factors to keep seeds viable. Experiments described here are concerned to the study of dormancy ant viability of seeds of grape cv. Patrícia, stored with two different moisture contents, either in moisture proof containers or paper bags, at temperaturss of 10°C, 20°C and 30°C, for 24 months. Samples were taken every two months during the first 12 months and at 6 months intervals in the second year, to determine seed viability and dormancy level. Storage, in the studied conditions, did not alter dormancy levei of the seeds. When stored in hermetical

  20. Dormancia y tratamientos pregerminativos en las semillas de Leucaena spp. cosechadas en suelo ácido Dormancy and pregerminative treatments in Leucaena spp. seeds harvested on acid soil

    Directory of Open Access Journals (Sweden)

    Yolanda González

    2009-12-01

    Full Text Available Se desarrolló un experimento con semillas de accesiones de Leucaena spp. cosechadas en suelo ácido y almacenadas bajo condiciones ambientales, para determinar el período e intensidad de la dormancia y su ruptura. Para ello se empleó un diseño de clasificación simple y cuatro réplicas, con los siguientes tratamientos: 1 semilla sin tratar (control; 2 corte de cubierta; y 3 agua a 80°C durante 2 minutos. En cada una de las accesiones hubo diferencias significativas entre los tratamientos aplicados y los mayores valores de germinación se encontraron con el corte de cubierta. Todas las accesiones mostraron estado dormático (entre 10 y 98%, el cual se apreció en la germinación del control y en la viabilidad con el corte de cubierta. Los mayores valores de dormancia en las semillas cosechadas en el 2006 se detectaron en L. macrophylla CIAT 17233, L. macrophylla CIAT 17231, L. diversifolia CIAT 17270 y L. leucocephala IH-1140, cuya dureza fue de 98,0; 97,0; 80,0 y 74,7%, respectivamente; en las cosechadas en el 2003 y 2004, los porcentajes de dureza fueron de 89,0; 69,0 y 60,0% para L. lanceolata CIAT 17252, L. macrophylla CIAT 17238 y L. leucocephala cv. K-67, respectivamente. Se concluye que las semillas de las accesiones presentaron dormancia poscosecha, que varió entre 10 y 98%. Además la escarificación térmica provocó su ruptura, por lo que se recomienda aplicar este procedimiento antes de la siembra a las semillas de Leucaena spp. que se cosechen en suelo ácido de Cascajal.A trial was conducted with seeds of Leucaena spp accessions harvested on acid soil and stored under ambient conditions, in order to determine the period and intensity of dormancy and its breaking. For that purpose a simple classification design and four replications were used, with the following treatments: 1 untreated seed (control; 2 coat cut; and 3 water at 80ºC for 2 minutes. In each one of the accessions there were significant differences among the

  1. Métodos de superação de dormência de sementes de barbatimão = Methods of breaking dormancy for seeds of Stryphnodendron

    Directory of Open Access Journals (Sweden)

    Cibele Chalita Martins

    2008-07-01

    Full Text Available O objetivo do trabalho foi identificar métodos para superar a dormência e promover a germinação de sementes de Stryphnodendron adstringens e Stryphnodendron polyphyllum. Sementes de ambas as espécies foram submetidas aos seguintes tratamentos desuperação de dormência: testemunha, escarificação mecânica (lixa número 220, H2O quente (temperatura inicial de 87oC por 5 e por 15 minutos, escarificação química com H2SO4 (95% por 30, 45, 60, 75, 90 e 105 minutos, choque térmico 1 (0oC e 50% UR por 1h e após imersão em água por 10 min. Ti=85oC Tf=57oC, choque térmico 2 (40oC e 40%UR por 6 h e após imersão em água por 10 min. Ti=0oC Tf=3oC, choque térmico 3 (40oC e 40% UR por 6h e após imersão em água por 10 min Ti=25oC Tf=25oC. Conclui-se que sementes pertencentes ao mesmo gênero, mas de espécies diferentes, respondem de forma diversa a alguns tratamentos de superação de dormência. Para ambas as espécies, a escarificação das sementes com H2SO4 (45 minutos ou lixa são métodos que podem ser utilizados com máxima eficiência para a superação da dormência e promoção da germinação.The aim of this research was to identify methods for breaking dormancy and promoting germination of Stryphnodendron adstringens and S. polyphyllum seeds. Seeds of both species were submitted to the following treatments for breaking dormancy: control; mechanical scarification (sandpaper number 220; hot water (initial temperature of 87°C for 5 and 15 minutes; chemical scarification with H2SO4 (95% for 30, 45, 60, 75, 90 and 105 minutes; thermalshock 1 (0°C and 50% RH for 1 h and thereafter 10 minutes into water Ti=85°C, Tf=57°C; thermic shock 2 (40°C and 40% RH for 6 h and thereafter 10 minutes into water, Ti=0°C, Tf=3°C; thermal shock 3 (40°C and 40% RH for 6h and thereafter 10 minutes into water, Ti=25°C, Tf=25°C. We concluded that seeds belonging to samegenus but from different species answered differently to some treatments

  2. Superação da dormência em sementes de crista de galo Overcoming of dormancy of crista de galo in seeds

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    Elane Grazielle Borba de Sousa Ferreira

    2012-05-01

    Full Text Available O presente trabalho teve como objetivo avaliar o efeito de diferentes tratamentos pré-germinativos na superação da dormência de sementes de Celosia cristata L., que foram submetidas aos seguintes tratamentos: choque térmico - exposição em estufa a 80°C por 5 minutos, escarificação química com ácido sulfúrico por um minuto, 30 segundos e 5 minutos, imersão das sementes intactas em água a 80°C até resfriamento, imersão das sementes intactas em água à temperatura ambiente por 24 horas e a testemunha - sem tratamento. Na avaliação do efeito dos tratamentos, foram determinados a porcentagem final, primeira contagem e índice de velocidade de germinação, como também o comprimento da raiz e do hipocótilo. As sementes de C. cristata L. quando oriundas de frutos maduros não necessitam da utilização de tratamentos para superação da dormência.This study had the objective of evaluating the effect of different pre-germination treatments for overcome of dormancy of Celosia cristata seeds, subjected to the following treatments: heat shock - exhibition in an oven at 80°C for 5 minutes, chemical scarification with sulfuric acid for 1 minute, 30 seconds and 5 minutes, immersion of intact seeds in water the 80°C at cooling and immersion of intact seeds in water for 24 hours, and the control - no treatment. We evaluated the following final percentage, first count and germination speed index, but also the length of the primary root and hypocotyl. The seeds of C. cristata when coming from ripe fruits do not require the use of treatments to overcoming dormancy.

  3. Storage of Pentatomid Eggs in Liquid Nitrogen and Dormancy of Trissolcus basalis (Wollaston) and Telenomus podisi Ashmead (Hymenoptera: Platygastridae) Adults as a Method of Mass Production.

    Science.gov (United States)

    Doetzer, A K; Foerster, L A

    2013-10-01

    The eggs of pentatomid species were evaluated to parasitism by Trissolcus basalis (Wollaston) and Telenomus podisi Ashmead after storage in liquid nitrogen. Adults which emerged from stored eggs were kept at 18°C for 120 and 180 days to investigate whether adult dormancy could be associated with host egg storage in liquid nitrogen as a method of mass production of these egg parasitoids. Eggs of Nezara viridula (L.) and Acrosternum pengue (Rolston) were successfully parasitized by T. basalis, as well as Piezodorus guildinii (Westwood) and Dichelops furcatus (F.) by T. podisi. The eggs of Edessa meditabunda (F.) were not parasitized by T. basalis. The emergence of T. podisi from eggs of Euschistus heros (F.) and Podisus nigrispinus (Dallas) stored for 6 months was lower than the control. Females of T. basalis and T. podisi that emerged from stored eggs were kept in dormancy at 18°C. Longevity of T. basalis was influenced by the storage time and sex, but not by the interaction of sex and storage time. For T. podisi, longevity was influenced by the storage time, sex, and by the interaction of sex and storage time. For T. basalis, storage in liquid nitrogen did not affect the fecundity of quiescent females, while the number of parasitized eggs by T. podisi decreased after storage. By the joint use of these techniques, it is possible to optimize mass production of T. basalis so that its life cycle can be monitored and synchronized with the life cycle and availability of hosts.

  4. In vitro binding of Sorghum bicolor transcription factors ABI4 and ABI5 to a conserved region of a GA 2-OXIDASE promoter: possible role of this interaction in the expression of seed dormancy.

    Science.gov (United States)

    Cantoro, Renata; Crocco, Carlos Daniel; Benech-Arnold, Roberto Luis; Rodríguez, María Verónica

    2013-12-01

    The precise adjustment of the timing of dormancy release according to final grain usage is still a challenge for many cereal crops. Grain sorghum [Sorghum bicolor (L.) Moench] shows wide intraspecific variability in dormancy level and susceptibility to pre-harvest sprouting (PHS). Both embryo sensitivity to abscisic acid (ABA) and gibberellin (GA) metabolism play an important role in the expression of dormancy of the developing sorghum grain. In previous works, it was shown that, simultaneously with a greater embryo sensitivity to ABA and higher expression of SbABA-INSENSITIVE 4 (SbABI4) and SbABA-INSENSITIVE 5 (SbABI5), dormant grains accumulate less active GA4 due to a more active GA catabolism. In this work, it is demonstrated that the ABA signalling components SbABI4 and SbABI5 interact in vitro with a fragment of the SbGA 2-OXIDASE 3 (SbGA2ox3) promoter containing an ABA-responsive complex (ABRC). Both transcription factors were able to bind the promoter, although not simultaneously, suggesting that they might compete for the same cis-acting regulatory sequences. A biological role for these interactions in the expression of dormancy of sorghum grains is proposed: either SbABI4 and/or SbABI5 activate transcription of the SbGA2ox3 gene in vivo and promote SbGA2ox3 protein accumulation; this would result in active degradation of GA4, thus preventing germination of dormant grains. A comparative analysis of the 5'-regulatory region of GA2oxs from both monocots and dicots is also presented; conservation of the ABRC in closely related GA2oxs from Brachypodium distachyon and rice suggest that these species might share the same regulatory mechanism as proposed for grain sorghum.

  5. Superação de dormência em sementes de Gleditschia amorphoides Taub. Overcoming of seed dormancy in Gleditschia amorphoides Taub.

    Directory of Open Access Journals (Sweden)

    Michele Fernanda Bortolini

    2011-05-01

    Full Text Available O trabalho teve como objetivo avaliar métodos para a superação da dormência de sementes de sucará. As sementes receberam os seguintes tratamentos: 1 testemunha; 2 escarificação mecânica; 3 escarificação mecânica + água/24h; 4 escarificação mecânica + água quente/24h; 5 água quente/24h; 6 ácido sulfúrico (H2SO4/1h; 7 H2SO4/2h; 8 H2SO4/1h + água/24h; 9 H2SO4/30min + água corrente/4h; 10 escarificação mecânica + água corrente/4h. O teste de germinação foi conduzido em rolos de papel Germitest acondicionados em câmara de germinação, à 25°C, com fotoperíodo de 12h por 26 dias. Avaliou-se também o tempo e a velocidade média de germinação. O delineamento experimental foi inteiramente casualizado, com quatro repetições de 25 sementes. O melhor desempenho germinativo foi registrado para as sementes submetidas à escarificação mecânica e química, com médias entre 76 e 98% de germinação, respectivamente, 2,17 a 2,88 dias para tempo médio de germinação e 0,46 a 0,47 sementes/dia para velocidade média de germinação, demonstrando serem estes os melhores métodos para superação da dormência de sementes dessa espécie.The objective of this research was to evaluate methods to overcome dormancy of seeds of Gleditschia amorphoides. For dormancy's overcoming the seeds received the following treatments: 1 control; 2 mechanical scarfication 3 mechanical scarfication + water/24h; 4 mechanical scarfication + hot water/24h; 5 hot water/24h; 6 sulfuric acid (H2SO4/1h; 7 H2SO4/2h; 8 H2SO4/1h + water/24h; 9 H2SO4/30min + flowing water/4h; 10 mechanical scarfication + flowing water/4h. Germination was done in rolls of Germitest conditioned in a germination chamber under 25°C, during 12h for 26 days. Percentage, time and average speed of germination were evaluated. The experimental design was completely casual with 10 treatments, 4 repetitions and 25 seeds. The best results were recorded for treatments with mechanical

  6. Quebra de dormência, viabilidade e conservação de sementes de buriti (Mauritia flexuosa Dormancy breaking, viability and conservation of Mauritia flexuosa seeds

    Directory of Open Access Journals (Sweden)

    Maria Roseli Nicoli Spera

    2001-12-01

    Full Text Available Os objetivos deste trabalho foram avaliar a viabilidade de embriões de buriti (Mauritia flexuosa L. pelo teste de tetrazólio e cultivo in vitro, o tratamento térmico na quebra de dormência das sementes, e o efeito do armazenamento em duas temperaturas na conservação das sementes. A viabilidade de embriões de sementes recém-colhidas foi condizente com os resultados de germinação de embriões in vitro, com valores superiores a 90%. O estudo da quebra de dormência foi feito com tratamento das sementes em temperaturas de 30, 35 e 40ºC por períodos de 15, 30 e 45 dias. Até 15 e 30 dias, os resultados obtidos foram maiores que os do controle. Sementes armazenadas em saco de plástico por um período de quatro meses e meio, sob temperatura de 20ºC, apresentaram resultados de germinação de embrião superiores a 90%, e sob temperatura de 30ºC houve perda total da viabilidade.The present work was conducted to evaluate the viability of embryos of Mauritia flexuosa L. by tetrazolium test and in vitro culture, high temperature treatment on dormancy breaking, and the effect of storage at different temperatures on seed conservation. The viability of newly harvested embryos presented a high correlation with the rate of embryo germination in vitro. The rate of viability was higher than 90% either when evaluated by the tetrazolium method or by in vitro embryo culture. Dormancy breaking of seeds was tested by treating the seeds under temperatures of 30, 35 and 40ºC for 15, 30, and 45 days. Great variation was observed among treatments, but, at least on day 15 and on day 30, the germination was higher than in the control. Seeds stored in plastic bags for four and a half months and temperature of 20ºC presented a germination rate higher than 90% while in the seeds stored at 30ºC the viability was zero.

  7. Study of Effects of Time, Quantity and Application Method of Benzylaminopurine and Gibberellic Acid Growth Regulators on Breaking Seed Dormancy of Kelussia odoratissima M.

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    S. Zafarian

    2013-06-01

    Full Text Available Karafs Kouhi (Kelussia odoratissima M. is one of the important medicinal plants of umbelliferae family and native of Zagros Mountains range, which is endangered due to illegal harvests. In order to accelerate breaking the seed dormancy of this plant, a factorial experiment based on completely randomized design with four replications, was carried in Faculty of Agriculture, Shahrekord University. The seeds of Karafs Kouhi from Saraghaseyed ecotype were treated under three time periods (25, 50, 75 and 100 days after planting, combination of enzylaminopurine (BAP (concentrations of 0, 0.75 and 1.5 mg/L and gibberellic acid (GA3 (concentrations of 0, 250 and 500 mg/L and application methods of these growth regulators (soaking seeds in the growth regulators and use of growth regulators directly on the medium. In this experiment, germination percentage, rootlet length and hypocotyl length were studied. The results indicated that 100 days after planting significantly (P≥0.01 showed the highest rates in the three studied traits. In this treatment, the germination percentage was 86.94%, rootlet length was 9.43 cm and hypocotyl length was 11.64 cm. Moreover, the interaction of the factors was not significant for all the traits. The best combination to increase germination percent, rootlet length and germination rate, was 0.75 mg/L BAP, 500 mg/L GA3 and direct use of growth regulators. To increase hypocotyl length, only 500 mg/L GA3 is recommended.

  8. PEMECAHAN DORMANSI DAN PERKECAMBAHAN ASAM KURANJI (Dialium indum L. SECARA MEKANIS DAN KIMIAWI Breaking Dormancy and Seeds Germination of Asam Kuranji (Dialium indum L. with Mechanical and Chemical

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    Bakti Nur Ismuhajaroh

    2016-08-01

    Full Text Available The purpose of the study was to find out the dormancy breaking and the seed germination of Asam kuranji (Dialium indum L. mechanically by sandpapering the seeds and chemically by immersing them in sulfuric acid (H2SO4. The experiment was conducted at the Plant Physiology Laboratory of Agricultural Faculty of Lambung Mangkurat University from June - August 2013 using Completely Randomized Design (CRD with 2 x 4 factorial. The first factor was the mechanical treatment  (s0 = without sandpaper and s1 = with sandpaper, the second factor was the chemical treatment (a0 = without immersion, a1 = 70% of H2SO4, a2 = 80% of H2SO4, and a3 = 90% of H2SO4. The data were analyzed by ANOVA at the level of 95% followed by Tukey's test at the level test of 95%. The results showed that the treatments of sandpapering and immersing the seeds significantly affected the % of germination, the length of radicle and the length of hypocotyl. The interaction between treatments of sandpapering and immersion indicated that the higher the concentration of H2SO4 immersion the higher the % of germination, the length of radicle and the length of hypocotyl. Keywords: germination, Dialium indum L., sandpaper, concentration, H2SO4

  9. Prevalence of Prostate Cancer Metastases after Intravenous Inoculation Provides Clues into the Molecular Basis of Dormancy in the Bone Marrow Microenvironment

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    Younghun Jung

    2012-05-01

    Full Text Available Bone is the preferred metastasis site of advanced prostate cancer (PCa. Using an in vivo murine model of human PCa cell metastasis to bone, we noted that the majority of animals that develop skeletal metastasis have either spinal lesions or lesions in the bones of the hindlimb. Much less frequently, lesions develop in the bones of the forelimb. We therefore speculated whether the environment of the forelimb bones is not permissive for the growth of PCa. Consequently, data on tumor prevalence were normalized to account for the number of PCa cells arriving after intravascular injection, marrow cellularity, and number of hematopoietic stem cell niches. None of these factors were able to account for the observed differences in tumor prevalence. An analysis of differential gene and protein levels identified that growth arrest specific-6 (GAS6 levels were significantly greater in the forelimb versus hindlimb bone marrow. When murine RM1 cells were implanted into subcutaneous spaces in immune competent animals, tumor growth in the GAS6-/- animals was greater than in GAS6+/+ wild-type animals. In an osseous environment, the human PC3 cell line grew significantly better in vertebral body transplants (vossicles derived from GAS6-/- animals than in vossicles derived from GAS6+/+ animals. Together, these data suggest that the differences in tumor prevalence after intravascular inoculation are a useful model to study the molecular basis of tumor dormancy. Importantly, these data suggest that therapeutic manipulation of GAS6 levels may prove useful as a therapy for metastatic disease.

  10. Winter warming delays dormancy release, advances budburst, alters carbohydrate metabolism and reduces yield in a temperate shrub

    DEFF Research Database (Denmark)

    Pagter, Majken; Andersen, Uffe Brandt; Andersen, Lillie

    2015-01-01

    Global climate models predict an increase in the mean surface air temperature, with a disproportionate increase during winter. Since temperature is a major driver of phenological events in temperate woody perennials, warming is likely to induce changes in a range of these events. We investigated ...

  11. Photoperiod-Induced Increases in Bone Mineral Apposition Rate in Siberian Hamsters and the Involvement of Seasonal Leptin Changes

    OpenAIRE

    Marie Kokolski; Francis J. Ebling; James R. Henstock; Susan I. Anderson

    2017-01-01

    The adipokine leptin regulates energy balance, appetite, and reproductive maturation. Leptin also acts on bone growth and remodeling, but both osteogenic and anti-osteogenic effects have been reported depending on experimental conditions. Siberian hamsters (Phodopus sungorus) have natural variation in circulating leptin concentrations, where serum leptin is significantly decreased during the short day (SD)-induced winter state. In summer long day (LD) photoperiods, appetite and body adiposity...

  12. Superação de dormência em sementes de manjericão (Ocimum basilicum L. Overcoming dormancy in seeds of basil (Ocimum basilicum L.

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    H.T.R. Amaro

    2012-01-01

    Full Text Available O objetivo do trabalho foi avaliar a eficiência de tratamentos pré-germinativos na superação da dormência de sementes de manjericão, produzidas no Horto de Plantas Medicinais da Unimontes, em fevereiro de 2011. Foram realizadas as seguintes determinações para avaliação da qualidade fisiológica das sementes: teor de água, germinação, primeira contagem de germinação, emergência de plântulas e índice de velocidade de emergência. O delineamento experimental utilizado foi inteiramente casualizado com quatro repetições de 50 sementes por tratamento, sendo T1- testemunha; T2 - pré esfriamento das sementes em câmara tipo BOD sob temperatura de 10ºC por 4 dias; T3 - embebição das sementes em água destilada por 24 horas; T4 - embebição das sementes em solução contendo KNO3 a 0,2 % por 5 minutos e T5 - sementes submetidas em água destilada a temperatura de 70ºC por 5 minutos. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste Scott - Knott a 5% de probabilidade. O tratamento pré esfriamento em câmara tipo BOD a 10ºC por 4 dias reduz a dormência e promove incrementos na qualidade fisiológica das sementes do manjericão.Aiming in order to assess the effectiveness of treatments to overcome dormancy in seeds of basil, an experiment was conducted at the Laboratory of Seed Analysis of Unimontes. Following determinations were performed to evaluate the physiological quality of seeds, water content, germination, first count germination, seedling emergence and emergence speed index. The experimental design was completely randomized design with four replications of 50 seeds per treatment, which consisted of: T1 - control, T2 - pre-cooling of the seed chamber BOD at a temperature of 10ºC for 4 days, T3 - soaking the seeds in water distilled for 24 hours, T4 - soaking the seeds in a solution containing 0,2% for 5 minutes and T5 - submitted seeds in distilled water at 70ºC for 5 minutes. Data

  13. Superação de dormência de maracujá-do-mato (Passiflora cincinnata Mast. Overcoming dormancy seeds of passion fruit (Passiflora cincinnata mast.

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    Manoel Xavier de Oliveira Júnior

    2010-06-01

    Full Text Available Com o objetivo de avaliar métodos de superação de dormência em sementes de maracujá-do-mato (P. cincinnata Mast., foi conduzido o experimento em casa de vegetação, na Universidade Estadual do Sudoeste do Estado da Bahia - UESB, Câmpus de Vitória da Conquista - BA, Brasil. O delineamento experimental foi o inteiramente casualizado, com sete tratamentos e três repetições, sendo 50 sementes por parcela: T1= sementes secas à sombra (Testemunha; T2= sementes secas ao sol (35 ±1ºC; T3= sementes secas à sombra com escarificação em lixa; T4= sementes secas à sombra tratadas com captana (0,2%; T5= sementes secas ao sol (35 ±1ºC com escarificação em lixa; T6= sementes secas à sombra aquecidas em banho-maria por 5 minutos, a 50ºC; T7= sementes secas à sombra aquecidas em banho-maria por 5 minutos, a 80ºC. As características avaliadas foram: porcentagem de germinação; porcentagem de emergência; índice de velocidade de emergência; altura das plântulas; diâmetro do caule; número de folhas; comprimento da raiz pivotante; massa da matéria seca total. Os resultados obtidos e analisados permitiram concluir que os melhores tratamentos para superação de dormência são o T3 (sementes secas à sombra com escarificação em lixa e T6 (sementes secas à sombra aquecidas em banho-maria por 5 minutos, a 50ºC.With the objective of evaluating the effect of different methods of dormancy break down on P.cincinnata Mast. seeds, a research was carried out in greenhouse at Bahia State University, Campus of Vitória da Conquista county, Bahia State, Brazil. The experimental design was a interely randomized blocks, composed of seven treatments and three replications, (T1-seeds dried in shade; T2-seeds dried in the sun; T3-seeds dried in shade followed by scarification; T4-seeds dried in shade and treated with captana (0,2%; T5-seeds dried in the sun followed by scarification; T6-seeds dried in shade and treated with hot water at 50ºC; T7

  14. SUPERAÇÃO DE DORMÊNCIA EM SEMENTES DE PIMENTA-DO-REINO (Piper nigrum L. DORMANCY OVERCOME IN BLACK PEPPER (Piper nigrum SEEDS

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    Marco Antônio Curado

    2007-09-01

    dormancy and reduce time for seedling production na experiment was carried out with seeds collected at the Alternative Medical Hospital in Goiânia, Brazil, at October 2000 and subject to the following treatments: a peeled seeds, b peelled seeds washed in running water for five minutes, c peelled seeds washed in running water for five minutes and soaked in a 50% detergent solution and then washed in running water for two minutes, d peelled seeds washed in running water for five minutes, then soaked in hypochloeite solution then washed for two minutes, e control. Four replications were used in a completely randomized design. After 21 days it was observed no germination in the control treatment. Pelling increased germination to 56%. The peeled and water washed seed treatments, and those with washed and then hypochlorite soaked seeds caused germination rate increase, but did not differ significantly from those which just the seed peel was removed (58 and 56% germination rate, respectively. The higher germination rate (73% was observed with peeled and washed seeds that were soaked in detergent solution, however no significant differences were found as compared to the water washed and hypochlorite soaked seed treatments.

    KEY-WORDS: Seeds; dormancy; black pepper.

  15. Overexpression of the kiwifruit SVP3 gene affects reproductive development and suppresses anthocyanin biosynthesis in petals, but has no effect on vegetative growth, dormancy, or flowering time.

    Science.gov (United States)

    Wu, Rongmei; Wang, Tianchi; McGie, Tony; Voogd, Charlotte; Allan, Andrew C; Hellens, Roger P; Varkonyi-Gasic, Erika

    2014-09-01

    SVP-like MADS domain transcription factors have been shown to regulate flowering time and both inflorescence and flower development in annual plants, while having effects on growth cessation and terminal bud formation in perennial species. Previously, four SVP genes were described in woody perennial vine kiwifruit (Actinidia spp.), with possible distinct roles in bud dormancy and flowering. Kiwifruit SVP3 transcript was confined to vegetative tissues and acted as a repressor of flowering as it was able to rescue the Arabidopsis svp41 mutant. To characterize kiwifruit SVP3 further, ectopic expression in kiwifruit species was performed. Ectopic expression of SVP3 in A. deliciosa did not affect general plant growth or the duration of endodormancy. Ectopic expression of SVP3 in A. eriantha also resulted in plants with normal vegetative growth, bud break, and flowering time. However, significantly prolonged and abnormal flower, fruit, and seed development were observed, arising from SVP3 interactions with kiwifruit floral homeotic MADS-domain proteins. Petal pigmentation was reduced as a result of SVP3-mediated interference with transcription of the kiwifruit flower tissue-specific R2R3 MYB regulator, MYB110a, and the gene encoding the key anthocyanin biosynthetic step, F3GT1. Constitutive expression of SVP3 had a similar impact on reproductive development in transgenic tobacco. The flowering time was not affected in day-neutral and photoperiod-responsive Nicotiana tabacum cultivars, but anthesis and seed germination were significantly delayed. The accumulation of anthocyanin in petals was reduced and the same underlying mechanism of R2R3 MYB NtAN2 transcript reduction was demonstrated. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  16. Decontamination effects of bark washing with a high-pressure washer on Peach [Prunus persica (L.) Batsch] and Japanese Persimmon (Diospyros kaki Thunb.) contaminated with radiocaesium during dormancy

    International Nuclear Information System (INIS)

    Sato, Mamoru; Abe, Kazuhiro; Kikunaga, Hidetoshi; Ohtsuki, Tsutomu; Takata, Daisuke; Tanoi, Keitaro; Muramatsu, Yasuyuki

    2015-01-01

    The effect of bark washing with a high-pressure washer on deciduous trees contaminated during dormancy by radiocaesium fallout derived from the Fukushima Daiichi Nuclear Power Plant accident was examined using peach [Prunus persica (L.) Batsch] and Japanese persimmon (Diospyros kaki Thunb.). Eighteen-year-old peach trees ('Akatsuki') were bark-washed twice with a high-pressure washer on July 5 and 27, 2011. Seven-year-old peach trees ('Kawanakajima Hakuto') were bark-washed on January 24, 2012, and thirty-year-old Japanese persimmon trees ('Hachiya') were bark-washed on December 21, 2011. For the peach trees, most of the bark was not removed by washing with a high-pressure washer. In contrast, the rough bark of Japanese persimmon was removed completely. No significant differences in the 137 Cs concentration of 'Akatsuki' fruit were found between the treatments conducted in the summer of 2011. Upon the bark washing of peach 'Akatsuki' trees in summer, the possibility of secondary contamination of leaves via the leachate containing 137 Cs was likely. The 137 Cs concentrations in fruits and leaves of peach 'Kawanakajima Hakuto' collected in summer 2012 were decreased significantly by washing treatment conducted in winter 2011–2012. In the year after treatment, the 137 Cs concentrations in fruits and leaves of Japanese persimmon were significantly decreased by the treatment. The effect of the bark washing on decreasing 137 Cs contents in fruits and leaves was greater in Japanese persimmon than in peach. The results for 'Kawanakajima Hakuto' and 'Hachiya' demonstrated the possibility of additive contamination. (author)

  17. Contrasting Strategies of Alfalfa Stem Elongation in Response to Fall Dormancy in Early Growth Stage: The Tradeoff between Internode Length and Internode Number

    Science.gov (United States)

    Wang, Zongli; Sun, Qizhong

    2015-01-01

    Fall dormancy (FD) in alfalfa (Medicago sativa L.) can be described using 11 FD ratings, is widely used as an important indicator of stress resistance, productive performance and spring growth. However, the contrasting growth strategies in internode length and internode number in alfalfa cultivars with different FD rating are poorly understood. Here, a growth chamber study was conducted to investigate the effect of FD on plant height, aboveground biomass, internode length, and internode number in alfalfa individuals in the early growth stages. In order to simulate the alfalfa growth environment in the early stage, 11 alfalfa cultivars with FD ratings from one to 11 were chosen and seeded at the greenhouse, and then were transplanted into an artificial growth chamber. The experimental design was a randomized complete block in a split-plot arrangement with three replicates. Plant height, above-ground biomass, internode length, and internode number were measured in early growth stage in all individuals. Our findings showed that plant height and the aboveground biomass of alfalfa did not significantly differ among 11 different FD rated cultivars. Also, internode length and internode number positively affected plant height and the aboveground biomass of alfalfa individuals and the average internode length significantly increased with increasing FD rating. However, internode number tended to sharply decline when the FD rating increased. Moreover, there were no correlations, slightly negative correlations, and strongly negative correlations between internode length and internode number in alfalfa individuals among the three scales, including within-FD ratings, within-FD categories and inter-FD ratings, respectively. Therefore, our results highlighted that contrasting growth strategies in stem elongation were adopted by alfalfa with different FD ratings in the early growth stage. Alfalfa cultivars with a high FD rating have longer internodes, whereas more dormant alfalfa

  18. Unraveling Key Metabolomic Alterations in Wheat Embryos Derived from Freshly Harvested and Water-Imbibed Seeds of Two Wheat Cultivars with Contrasting Dormancy Status

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    Aayudh Das

    2017-07-01

    Full Text Available Untimely rains in wheat fields during harvest season can cause pre-harvest sprouting (PHS, which deteriorates the yield and quality of wheat crop. Metabolic homeostasis of the embryo plays a role in seed dormancy, determining the status of the maturing grains either as dormant (PHS-tolerant or non-dormant (PHS-susceptible. Very little is known for direct measurements of global metabolites in embryonic tissues of dormant and non-dormant wheat seeds. In this study, physiologically matured and freshly harvested wheat seeds of PHS-tolerant (cv. Sukang, dormant and PHS-susceptible (cv. Baegjoong, non-dormant cultivars were water-imbibed, and the isolated embryos were subjected to high-throughput, global non-targeted metabolomic profiling. A careful comparison of identified metabolites between Sukang and Baegjoong embryos at 0 and 48 h after imbibition revealed that several key metabolic pathways [such as: lipids, fatty acids, oxalate, hormones, the raffinose family of oligosaccharides (RFOs, and amino acids] and phytochemicals were differentially regulated between dormant and non-dormant varieties. Most of the membrane lipids were highly reduced in Baegjoong compared to Sukang, which indicates that the cell membrane instability in response to imbibition could also be a key factor in non-dormant wheat varieties for their untimely germination. This study revealed that several key marker metabolites (e.g., RFOs: glucose, fructose, maltose, and verbascose, were highly expressed in Baegjoong after imbibition. Furthermore, the data showed that the key secondary metabolites and phytochemicals (vitexin, chrysoeriol, ferulate, salidroside and gentisic acid, with known antioxidant properties, were comparatively low at basal levels in PHS-susceptible, non-dormant cultivar, Baegjoong. In conclusion, the results of this investigation revealed that after imbibition the metabolic homeostasis of dormant wheat is significantly less affected compared to non

  19. Superação da dormência de sementes de carrapicho-beiço-de-boi Dormancy overcoming in Desmodium tortuosum seeds

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    Cibele C. Martins

    1997-01-01

    220 e debulha mecânica, empregando-se processa dor, podem ser recomendados para a superação da dormência e promoção da germinação de sementes de D. tortuosum.In order to obtain a process capable of speeding the germination of D. tortuosum (Sw. DC. seeds, two experiments were conducted with one-seeded loment (control segments submitted to manual threshing; manual threshing followed by chemical scarification, also manual, with sandpaper no 220; mechanical threshing (home processor; chemical scarification with H,S0, (95% for 1, 5, and 8 min; pre-heating at 530C for 4, 10, and 16 h in forced-air oven; imbibition with H2O at 800C for 1, 3, 5, and 10 min; H20 at 27 C for 2 h; and imbibition with thermal swich (H2O at 80 0C/5 min an d H20 at 130 C/ 1 min . For treat ment evaluation one used germination (G, soil seed ling emergence (E , first count of germination (FG, and emergence (FE tests, germination (I. V.G. and emergence (I. V.E. seed index, and seed ling length (S L. A completely randomized block design with 4 replications of 100 (G, FG, I.V. G. or 20 seeds (SL per treatment in the first experiment, and 4 replications of 50 (G, FG, I.V.G. or 100 seeds (E, FE, I. V.E. per treatment on the second experiment was used. In the first experiment, the treatments which showed a significant dormancy decrease (D and consequent germination increase (G in comparison with the control (D = 82%; G =15% were, in a decreasing efficacy order: manual threshing and scarification (D=3%; G=92%, mechanical thre shing (D = 13%; G = 81%, imbibition in H20 at 800C for 1 min (D = 68%; G = 29% and 3 min (D=65%; G=32%. The second experiment (control with D = 93%; G = 3% pointed out: threshing and manual scarification (D=2%; G=93%, mechanical threshing (D = 2%; G = 87%, imbibition into H20 at 800C for 5min and thermal switch (both with D = 85% and G=11%. The FC, I.V.G ., I.V. E., SL, and E vigour tests confirmed these results. Thus, manual scarification with 220 sandpaper and mechanical

  20. A comparative bear model for immobility-induced osteopenia

    Science.gov (United States)

    Milbury, P. E.; Vaughan, M. R.; Farley, S.; Matula, G. J. Jr; Convertino, V. A.; Matson, W. R.

    1998-01-01

    The National Institutes of Health (NIH) and the National Aeronautics and Space Administration (NASA) are seeking solutions to the human problem of osteopenia, or immobility-induced bone loss. Bears, during winter dormancy, appear uniquely exempted from the debilitating effects of immobility osteopenia. NIH and ESA, Inc. are creating a large database of metabolic information on human ambulatory and bedrest plasma samples for comparison with metabolic data obtained from bear plasma samples collected in different seasons. The database generated from NASA's HR113 human bedrest study showed a clear difference between plasma samples of ambulatory and immobile subjects through cluster analysis using compounds determined by high performance liquid chromatography with coulometric electrochemical array detection (HPLC-EC). We collected plasma samples from black bears (Ursus americanus) across 4 seasons and from 3 areas and subjected them to similar analysis, with particular attention to compounds that changed significantly in the NASA human study. We found seasonal differences in 28 known compounds and 33 unknown compounds. A final database contained 40 known and 120 unknown peaks that were reliably assayed in all bear and human samples; these were the primary data set for interspecies comparison. Six unidentified compounds changed significantly but differentially in wintering bears and immobile humans. The data are discussed in light of current theories regarding dormancy, starvation, and anabolic metabolism. Work is in progress by ESA Laboratories on a larger database to confirm these findings prior to a chemical isolation and identification effort. This research could lead to new pharmaceuticals or dietary interventions for the treatment of immobility osteopenia.

  1. Seeds of Brassicaceae weeds have an inherent or inducible response to the germination stimulant karrikinolide.

    Science.gov (United States)

    Long, Rowena L; Stevens, Jason C; Griffiths, Erin M; Adamek, Markus; Gorecki, Marta J; Powles, Stephen B; Merritt, David J

    2011-10-01

    Karrikinolide (KAR(1)) is a smoke-derived chemical that can trigger seeds to germinate. A potential application for KAR(1) is for synchronizing the germination of weed seeds, thereby enhancing the efficiency of weed control efforts. Yet not all species germinate readily with KAR(1), and it is not known whether seemingly non-responsive species can be induced to respond. Here a major agronomic weed family, the Brassicaceae, is used to test the hypothesis that a stimulatory response to KAR(1) may be present in physiologically dormant seeds but may not be expressed under all circumstances. Seeds of eight Brassicaceae weed species (Brassica tournefortii, Raphanus raphanistrum, Sisymbrium orientale, S. erysimoides, Rapistrum rugosum, Lepidium africanum, Heliophila pusilla and Carrichtera annua) were tested for their response to 1 µm KAR(1) when freshly collected and following simulated and natural dormancy alleviation, which included wet-dry cycling, dry after-ripening, cold and warm stratification and a 2 year seed burial trial. Seven of the eight Brassicaceae species tested were stimulated to germinate with KAR(1) when the seeds were fresh, and the remaining species became responsive to KAR(1) following wet-dry cycling and dry after-ripening. Light influenced the germination response of seeds to KAR(1), with the majority of species germinating better in darkness. Germination with and without KAR(1) fluctuated seasonally throughout the seed burial trial. KAR(1) responses are more complex than simply stating whether a species is responsive or non-responsive; light and temperature conditions, dormancy state and seed lot all influence the sensitivity of seeds to KAR(1), and a response to KAR(1) can be induced. Three response types for generalizing KAR(1) responses are proposed, namely inherent, inducible and undetected. Given that responses to KAR(1) were either inherent or inducible in all 15 seed lots included in this study, the Brassicaceae may be an ideal target for

  2. Superação da dormência e avaliação da qualidade fisiológica de sementes de Sesbania virgata Dormancy break and evaluation of physiological quality of Sesbania virgata seeds

    Directory of Open Access Journals (Sweden)

    Valquíria Nogueira Camargos

    2008-12-01

    Full Text Available A avaliação da qualidade fisiológica de lotes de sementes de Sesbania virgata é dificultada pela dormência inerente à espécie, bem como pela inadequação metodológica de testes disponíveis. Para desenvolver procedimentos adequados à avaliação da qualidade das sementes de S. virgata, foram avaliados métodos tanto para quebra de dormência como para realização do teste de tetrazólio. Em uma primeira fase, as sementes de cinco lotes foram submetidas a tratamentos para quebra de dormência: lixa, ácido e corte do tegumento, previamente ao teste de germinação. Para caracterização dos lotes e adequação da metodologia do teste de tetrazólio, na segunda fase, as sementes foram lixadas na região oposta ao eixo embrionário, e submetidas aos seguintes testes: tetrazólio, germinação, velocidade de emergência, peso de matéria fresca e de matéria seca de plântulas. Foram utilizados dois métodos de pré-condicionamento: embebição em papel por 18 h a 30 ºC e imersão em água por 12 h a 30 ºC e três períodos (uma, duas e três horas de imersão em solução de tetrazólio 0,5%. Na análise do perfil dos lotes de S. virgata foram detectadas variações na qualidade fisiológica pelos resultados dos testes de vigor e germinação. O método de escarificação com lixa possibilitou a quebra de dormência das sementes de S. virgata,e o pré-condicionamento das sementes em papel com embebição em solução de tetrazólio 0,5% por duas horas é um procedimento adequado para avaliação da viabilidade das sementes.The evaluation of Sesbania virgata seed physiological quality is hampered by its intrinsic seed dormancy and inadequate methodologies among available tests. To develop an adequate procedure to evaluate S. virgata seed quality, methods for dormancy breaking and tetrazolium test accomplishment were evaluated. In a first stage, seeds from five lots were submitted to dormancy breaking methods: sandpaper, acid and

  3. Superação de dormência de sementes como estratégia para restauração florestal de pastagem tropical Seed dormancy overcoming as a strategy for forest restoration in tropical pasture

    Directory of Open Access Journals (Sweden)

    Silvia Rahe Pereira

    2013-02-01

    Full Text Available O objetivo deste trabalho foi avaliar a influência de tratamentos de superação da dormência de sementes sobre a taxa e o tempo de emergência de espécies arbóreas de Fabaceae, e sobre seu estabelecimento, quando reintroduzidas em pastagem, no Cerrado. Foram realizados experimentos em casa de vegetação e em campo (pastagem de Urochloa brizantha, com as espécies Mimosa caesalpiniifolia, Peltophorum dubium, Pterogyne nitens, Dimorphandra mollis, Copaifera langsdorffii e Hymenaea stigonocarpa, submetidas ou não aos seguintes tratamentos de superação de dormência: D. mollis e H. stigonocarpa, escarificação mecânica; C. langsdorffii e M. caesalpiniifolia, escarificação química com H2SO4; P. nitens, punção do tegumento; e P. dubium, imersão em água a 80ºC. O estabelecimento em campo foi monitorado por 21 meses. A superação de dormência promoveu, em casa de vegetação, maior emergência de quatro das seis espécies avaliadas, e, no campo, de cinco espécies. Além disso, reduziu o tempo de emergência das espécies e aumentou o recrutamento de M. caesalpiniifolia, P. nitens, D. mollis e H. stigonocarpa, aos 127 dias, e de H. stigonocarpa aos 659 dias. Os tratamentos de superação de dormência podem aumentar a eficiência da semeadura direta, em projetos de restauração de áreas degradadas no Cerrado, ao promover maior emergência das sementes e o estabelecimento das plantas.The objective of this work was to evaluate the influence of seed dormancy overcoming treatments on the rate and time of emergence of Fabaceae tree species, and on their recruitment when reintroduced in a tropical pasture, in the Brazilian Cerrado. Experiments were carried out in greenhouse and field (Urochloa brizantha pasture, with the species Mimosa caesalpiniifolia, Peltophorum dubium, Pterogyne nitens, Dimorphandra mollis, Copaifera langsdorffii and Hymenaea stigonocarpa, subjected or not to the following treatments of dormancy break: D. mollis and

  4. Transcriptional activation of cyclin-dependent kinase inhibitor, p21waf1 gene by treatment with a differentiation inducing agent, vesnarinone in a human salivary gland cancer cell line.

    Science.gov (United States)

    Omotehara, F; Nakashiro, K; Uchida, D; Hino, S; Fujimori, T; Kawamata, H

    2003-03-01

    Recently, a new concept for cancer therapy termed "tumor dormancy therapy" has been proposed. The concept of this therapy is to prolong the survival time of cancer patients while maintaining their quality of life. We have been developing a differentiation-inducing therapy, which is included in the tumor dormancy therapy, for salivary gland cancer. In this study, we examined the effect of a differentiation-inducing drug, Vesnarinone on the growth of several cancer cells, and examined the molecular mechanism by which Vesnarinone induces the cyclin dependent kinase inhibitor, p21waf1 in the cancer cells. Vesnarinone significantly suppressed the growth of TYS (salivary gland cancer cells), PC3 (prostate cancer cells), and A431 (squamous cell cancer cells). Furthermore, Vesnarinone dose-dependently enhanced the expression of p21waf1 mRNA in TYS cells. Using the luciferase reporter assay it was found that the enhancement of p21waf1 mRNA expression by Vesnarinone was through direct transcriptional activation of the p21waf1 promoter. Thus, analyzing the molecular mechanisms of differentiation inducing drugs may lead to the development of a new therapeutic strategy for several human malignancies, including salivary gland cancer.

  5. Estimating COCOM Natural Background Dormancy

    Science.gov (United States)

    2015-04-01

    for North America , South America , Asia, Africa , and Europe. The maps were drafted using the fol- lowing three principles (Chambers 1967): 1...for exam- ple, is number 6, Earth Brown, indicating needle-leaf deciduous forest and tundra during the dormant or dry season, barren areas, bare rock...moisture, greening the forest and savanna, or drying when they leave, depending upon the season. The World Color Regions Atlas illustrates the monthly

  6. Escape from Tumor Cell Dormancy

    Science.gov (United States)

    2012-10-01

    for metastatic cell arrest in distant organs. Neoplasia, 7(5), 522-7 (2005) 170. K. A . Paschos, D. Canovas and N. C. Bird : The role of cell adhesion...overnight in a 608C oven . Polymerized PDMS micropatterned stamps were peeled off the silicon master and used for patterning the PEG–fibrinogen...to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE

  7. Syndecan-1 and Metastasis Dormancy

    Science.gov (United States)

    2015-09-01

    Sdc1 WT vs Sdc1 KO mice (p = 0.36). - 5 - Major Task 2: Optimize 3D lung microenvironment assay Subtask 1: Transduce HMVEC-L with E4ORF1 and mCherry...micro-channel devices (see below) but have not yet transduced them with E4ORF1 nor labeled them. If we succeed in generating defined vascular

  8. High autumn temperature delays spring bud burst in boreal trees, counterbalancing the effect of climatic warming

    Energy Technology Data Exchange (ETDEWEB)

    Heide, O. M. [Agricultural Univesity of Norway, Department of Biology and Nature Conservation, As (Norway)

    2003-09-01

    The effect of temperature during short-day dormancy induction on the duration and stability of bud dormancy was examined in three boreal tree species (2 birches and 1 alder) grown in a controlled environment. The phenology of the latitudinal range of birch populations, and the relationship between spring bud burst and autumn and spring temperatures were also studied. Results showed that during short-day dormancy induction in the autumn high temperatures delayed bud burst in the following spring in both controlled and natural environments. It is suggested that this response to higher autumn temperatures may be a manifestation of a general synergism between high temperature and short-day photoperiodic processes, and may be an adaptive mechanism common to boreal trees. It is further conjectured that this mechanism may be important in counterbalancing the potentially adverse effects of higher winter temperatures on dormancy stability of boreal trees during climate warming. 23 refs., 2 tabs., 4 figs.

  9. Induced Abortion

    Science.gov (United States)

    ... Education & Events Advocacy For Patients About ACOG Induced Abortion Home For Patients Search FAQs Induced Abortion Page ... Induced Abortion FAQ043, May 2015 PDF Format Induced Abortion Special Procedures What is an induced abortion? What ...

  10. Tumor-reactive immune cells protect against metastatic tumor and induce immunoediting of indolent but not quiescent tumor cells.

    Science.gov (United States)

    Payne, Kyle K; Keim, Rebecca C; Graham, Laura; Idowu, Michael O; Wan, Wen; Wang, Xiang-Yang; Toor, Amir A; Bear, Harry D; Manjili, Masoud H

    2016-09-01

    Two major barriers to cancer immunotherapy include tumor-induced immune suppression mediated by myeloid-derived suppressor cells and poor immunogenicity of the tumor-expressing self-antigens. To overcome these barriers, we reprogrammed tumor-immune cell cross-talk by combined use of decitabine and adoptive immunotherapy, containing tumor-sensitized T cells and CD25(+) NKT cells. Decitabine functioned to induce the expression of highly immunogenic cancer testis antigens in the tumor, while also reducing the frequency of myeloid-derived suppressor cells and the presence of CD25(+) NKT cells rendered T cells, resistant to remaining myeloid-derived suppressor cells. This combinatorial therapy significantly prolonged survival of animals bearing metastatic tumor cells. Adoptive immunotherapy also induced tumor immunoediting, resulting in tumor escape and associated disease-related mortality. To identify a tumor target that is incapable of escape from the immune response, we used dormant tumor cells. We used Adriamycin chemotherapy or radiation therapy, which simultaneously induce tumor cell death and tumor dormancy. Resultant dormant cells became refractory to additional doses of Adriamycin or radiation therapy, but they remained sensitive to tumor-reactive immune cells. Importantly, we discovered that dormant tumor cells contained indolent cells that expressed low levels of Ki67 and quiescent cells that were Ki67 negative. Whereas the former were prone to tumor immunoediting and escape, the latter did not demonstrate immunoediting. Our results suggest that immunotherapy could be highly effective against quiescent dormant tumor cells. The challenge is to develop combinatorial therapies that could establish a quiescent type of tumor dormancy, which would be the best target for immunotherapy. © The Author(s).

  11. SEMENTES DE SAPOTI (Achras sapota L.: DORMÊNCIA E EMERGÊNCIA SAPODILLA (Achras sapota L. SEEDS: DORMANCY AND EMERGENCE

    Directory of Open Access Journals (Sweden)

    Acilon da Silva

    2007-09-01

    Full Text Available

    Este trabalho teve como objetivo avaliar a eficiência de diferentes métodos pré-germinativos para superar a dormência de sementes de sapoti (Achras sapota L.. Os tratamentos utilizados foram: testemunha, imersão em água a 60°C e 70°C até resfriamento à temperatura ambiente (27ºC; escarificação com lixa no 100, seguida de embebição em água à temperatura ambiente por 24 e 48 horas; e estratificação, em areia, na geladeira (10±1°C por cinco dias. As sementes foram semeadas a uma profundidade de 2 cm, em bandejas com substrato areia + esterco (3:1 e distribuídas em quatro repetições de 25 sementes, sob condições de casa de vegetação no Setor de Sementes do Centro de Ciências Agrárias da UFPB, Areia - PB. A imersão em água a 60°C até resfriamento e a escarificação com lixa no 100, seguida de embebição em água por 24 horas, apresentaram maiores percentagens de emergência (72% em relação aos demais tratamentos pré-germinativos, embora não tenham diferido estatisticamente da testemunha (68%. Com relação ao índice de velocidade de emergência, os menores valores foram obtidos quando se utilizou a escarificação com lixa no 100 seguida de embebição por 48 horas (0,13, e a imersão em água a 70°C até resfriamento (0,18. Portanto, não devem ser usados como tratamentos pré-germinativos em sementes de sapoti.

    PALAVRAS-CHAVE: Achras sapota; métodos pré-germinativos; velocidade de emergência.

    The aim of the present research was to evaluate the efficiency of different pre-germinating methods for breaking the dormancy of sapodilla (Achras sapota L. seeds. The treatments were: control; immersion in water at 60 and 70°C until cooling to the environment temperature (27°C, scarification with sandpaper

  12. Storage and methods for overcoming dormancy of the coral tree seedsArmazenamento e métodos para a superação da dormência de sementes de mulungu

    Directory of Open Access Journals (Sweden)

    Ana Claudia da Silva

    2013-03-01

    Full Text Available The coral tree (Erythrina velutina Willd. is an arboreal species that occurs in northeast Brazil and is used in popular medicine to fight cough, asthma, oral diseases, nervous breakdowns, muscle aches and fevers. The process of formation of seedlings of the species is difficult because of the occurrence of seed dormancy. The aim of this study was to evaluate the effect of different methods for overcoming dormancy in seeds of the coral tree stored in different conditions and periods. The experimental design was completely randomized in factorial scheme 5 x 2 (methods for overcoming dormancy and storage types, in four replicates of 25 seeds. The methods used were (S1 control, (S2 scarification opposite the micropyle; (S3 by the scarification micropyle; (S4 seeds immersed in water at 80 °C for five minutes and (S5 seeds immersed in water at 100 °C for two minutes. The storage types were for 25 months at cold chamber and for a month at the laboratory environment. The characteristics evaluated were emergence percentage (PE, time of emergence (TM, shoot length (CPA and root (CR, diameter (D, leaf number (NF, dry biomass of roots (MSPA and of shoots (MSR of seedlings. The emergence percentage was low in treatments S1, S4 and S5 and the seeds stored for one month were more affected when immersed in hot water. The highest values of CPA, CR, MSPA and NF treatments were observed in S2 and S3, which occurred in the lowest average time of emergence. The tegument dormancy of seeds of Erythrina velutina is overcome by scarification with sandpaper on the end opposite the micropyle or next to it. The seed dormancy is not affected by the types of storage and is not overcome by immersion in hot water. O mulungu (Erythrina velutina Willd. é uma espécie arbórea que ocorre no Nordeste brasileiro utilizada na medicina popular no combate a tosse, asma, afecções bucais, crises nervosas, dores musculares e febres. O processo de formação de mudas da espécie

  13. Latencia y banco de semillas en plantas de la región mediterránea de Chile central Seed bank and dormancy in plants of the Mediterranean region of central Chile

    Directory of Open Access Journals (Sweden)

    JAVIER A. FIGUEROA

    2004-03-01

    un modelo estructural y funcional del banco de semillas para el matorral de Chile central, que debería ser enriquecido con futuras investigacionesSeed banks on Mediterranean regions display characteristics that distinguish them from the seed banks of other regions. A seed bank is the concentration of viable propagules buried in the soil for variable periods of time. Seed banks in the Chilean matorral are chiefly transient and functionally similar to seed banks in other Mediterranean ecosystems not disturbed by fire, except for those of Australia. A transient seed bank is that composed of seeds that cannot survive in the upper levels of the soil for more than 1 year. The density of herb seeds in the Chilean matorral soil is one of the highest among Mediterranean ecosystems anywhere in the world, and a large proportion of these seeds is made up of seeds without dormancy that germinate easily, particularly annual grasses. With respect to the dormancy mechanisms that may be responsible for the behavior of these seeds stored in the transient bank, our analysis revealed the following germination syndromes: (1 species whose seeds must be stratified in cold due to the presence of physiological dormancy (particularly introduced herbs, (2 species whose seeds must be scarified with acids or mechanical means due to the presence of physical dormancy (mainly native woody species and, (3 species that present physiological dormancy and need heat stratification to activate germination (both native and introduced species. These syndromes determine that the timing of germination in central Chile has an autumn and an early spring phase. Besides, there is absence of sporadic germination syndromes for the components of a persistent seed bank. We propose a structural and functional model of the seed bank for the matorral of central Chile that should be enriched with future research

  14. Genetic control of seed dormancy and pre-harvest sprouting in wheat Controle genético da dormência e da germinação precoce em trigo

    Directory of Open Access Journals (Sweden)

    Claudinei Andreoli

    2006-12-01

    Full Text Available Pre-harvest sprouting (PHS damage leads to occasional massive losses in all wheat producing areas, causing downgrading of grain quality, that severely limits end-use applications and results in substantial financial losses to farmers and food processors. Red grain color is a traditional marker for resistance to sprouting in wheat breeding programs, however red-grained genotype alone does not always guarantee effective resistance. The objective of this work was to find genes for resistance to PHS and investigate its inheritance in Brazilian wheat cultivars. Genetic variation for dormancy was investigated in the parents, F1 and 300 F2 lines derived from the cross Frontana × OR1 and its reciprocal. The germination/dormancy sprouted grains was evaluated on fifty seeds per replication, germinated in paper towel rolls at 20ºC for 5 days. A bimodal distribution for dormancy occurred in the Frontana/OR1 and OR1/Frontana derived F2 populations. The mean ratio of dormant and non-dormant seeds of the cross and its reciprocal was 85:1115, fitting a digenic model of 1:15 (P Germinação precoce na espiga (PHS ocasiona perdas significativas nas regiões produtoras de trigo, causando depreciação na qualidade do produto final, o que resulta em prejuízos para os produtores e os moageiros. A cor vermelha do grão é um marcador tradicional para resistência à germinação nos programas de melhoramento de trigo, todavia, o genótipo de grão vermelho sózinho não garante resistência efetiva. O objetivo desse trabalho foi encontrar gene(s para resistência à PHS e estudar a herança do caráter dormência de semente nos cultivares de trigo brasileiro. A variação genética para dormência foi investigada nos parentais, no F1 e em 300 linhas F2 derivadas do cruzamento de Frontana × OR1, e o cruzamento recíproco. Os grãos brotados (sprouted e os dormentes foram avaliados pelo teste de germinação, em rolo de papel, a 20º C por 5 dias. Observou-se uma

  15. Overcoming seed dormancy and early growth of seedlings of Spondias tuberosa, Arr. CâmaraSuperação de dormência de sementes e crescimento inicial de plântulas de umbuzeiro

    Directory of Open Access Journals (Sweden)

    Janete Motta da Silva Gonzaga

    2012-08-01

    Full Text Available Pre-germination treatments such as scarification and the use of growth regulators can provide the dormancy breaking in seeds and enhance the emergence and development of seedlings. The aim of this study was to determine appropriate treatments to overcome seed dormancy and enhance the initial growth of seedlings of Spondias tuberosa. We used a randomized design in factorial 2 x 4, with the following factors: seeds scarified or not scarified and then soaked in water or aqueous solutions of gibberellin, cytokinin and ethylene, with 4 replicates and 15 seeds. There was no significant interaction between scarification treatments and use of growth regulators. Mechanical scarification and soaking seeds in solutions containing umbuzeiro growth regulators does not increase the percentage of seedling emergence, however soaking in a solution of Ethrel at 100 ppm provides higher speed of emergence and root development. Tratamentos pré-germinativos, como a escarificação e o uso de reguladores de crescimento, podem proporcionar a superação de dormência em sementes e incrementar a emergência e o desenvolvimento de plântulas. O objetivo da presente pesquisa foi determinar tratamentos adequados para a superação da dormência de sementes e potencialização do crescimento inicial de plântulas de umbuzeiro. Utilizou-se o delineamento inteiramente casualizado, em fatorial 2 x 4, sendo os fatores: sementes escarificadas ou não escarificadas e, posteriormente, imersas em água ou soluções aquosas de giberelina, citocinina ou etileno, com 4 repetições de 15 sementes. Não houve interação significativa entre os tratamentos escarificação e uso de reguladores de crescimento. A escarificação mecânica e a embebição de sementes de umbuzeiro em soluções contendo reguladores de crescimento não aumenta a percentagem de emergência de plântulas, entretanto a embebição em solução de Ethrel a 100 ppm proporciona maior velocidade de emergência e

  16. Dormancy break in seeds of "quina" (Strychnos pseudoquina A. St.-Hil. Superação da dormência de sementes de quina (Strychnos pseudoquina A. St.-Hil.

    Directory of Open Access Journals (Sweden)

    J.M. Vasconcelos

    2011-01-01

    Full Text Available "Quina" (Strychnos pseudoquina A. St. Hil is a medicinal plant species from the Brazilian Cerrado. As its seeds show dormancy, they were subjected to the treatments pre-cooling at 5ºC during 7 days, pre-heating at 40ºC during 7 days, pre-soaking in sulfuric acid PA during 5 and 15 min, pre-soaking in boiling water during 5 and 15 min, pre-soaking in 100 and 200 ppm gibberellic acid during 48 h, pre-soaking in distilled water during 24 and 48 h, and mechanical scarification to break dormancy. Counts were daily conducted from the 2nd day after the experiment implementation until the germination stabilization at the 65th day. The germination speed index (GSI and the germination percentage were evaluated. Germination rates above 96% were reached in seeds pre-soaked in water during 48 h and substrate moistened with water or KNO3.A quina (Strychnos pseudoquina A. St.-Hil é espécie medicinal do Cerrado Brasileiro. As sementes apresentam dormência e, por isso, foram submetidas aos tratamentos pré-resfriamento a 5ºC durante 7 dias, pré-aquecimento a 40ºC durante 7 dias, pré-embebição em ácido sulfúrico P.A. durante 5 e 15 minutos, pré-embebição em água fervente durante 5 e 15 minutos, pré-embebição em ácido giberélico a 100 e 200 ppm, durante 48 horas, pré-embebição em água destilada durante 24 e 48 horas e escarificação mecânica, visando à superação da dormência. Foram realizadas contagens diárias entre o 2º dia após a implantação do experimento até a estabilização da germinação, que ocorreu no 65º dia. Foram avaliados o índice de velocidade de germinação (IVG e a porcentagem de germinação. Taxas de germinação acima de 96% foram atingidas em sementes pré-embebidas em água durante 48 horas e substrato umedecido com água ou KNO3.

  17. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    Directory of Open Access Journals (Sweden)

    Or Sperling

    Full Text Available Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq. cm(-3 yr(-1 on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

  18. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    Science.gov (United States)

    Sperling, Or; Earles, J Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A

    2015-01-01

    Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC) availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0 °C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq.) cm(-3) yr(-1) on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics.

  19. Tecnologia alternativa para a quebra de dormência das sementes de pau-de-balsa (Ochroma lagopus Sw., Bombacaceae Alternative technology for breaking dormancy of balsa wood (Ochroma lagopus Sw., Bombacaceae seeds

    Directory of Open Access Journals (Sweden)

    Antenor P. Barbosa

    2004-01-01

    Full Text Available Este trabalho, teve como objetivo estudar a germinação das sementes de pau-de-balsa (Ochroma lagopus Sw., Bombacaceae em diferentes estágios de maturação aparente dos frutos; a germinação das sementes provenientes de árvores com diferentes diâmetros a altura do peito (DAP e a germinação das sementes tratadas para quebra de dormência. No primeiro experimento, avaliou-se a germinação das sementes dos frutos verdes, verdosos (verde amarelado, negros (fruto fechado e negros deiscentes (fruto aberto com painas expostas. No segundo, a germinação das sementes de árvores da mesma idade e com diferentes DAP's: pequeno (5,4 cm, médio (9,1 cm e grande (13,2 cm. No terceiro, a germinação das sementes com diferentes quebra de dormência: testemunha; água por 24 e 48 horas; água a 80ºC até esfriar; H2SO4 por ½ e 1 minuto com e sem paina; queima da paina em peneira metálica; e semeio de sementes com a paina. As sementes germinaram em gerbox sobre papel de filtro, em câmara de germinação, nas temperaturas de 20ºC, 30ºC e 25ºC, no primeiro, segundo e terceiro experimentos, respectivamente. As sementes de pau-de-balsa germinaram melhor e mais rápido quando coletadas de frutos negros a negros deiscentes, ou quando coletadas de árvores com menor e médio diâmetros, ou quando tratadas com água quente a 80ºC até esfriar, ou com ácido sulfúrico por ½ ou 1 minuto com ou sem paina. Os tratamentos com ácido tem a vantagem de quebrar a dormência da semente e dissolver a paina. As sementes recém colhidas e germinadas não apresentaram dormência tegumentar.The objective of this study was to evaluate the germination of "pau-de-balsa" (Ochroma lagopus Sw., Bombacaceae seed as a function of maturation stages of fruits, the germination of seeds harvested from trees with different diameters at height breast (DBH, and the germination of seed with different treatments to break dormancy. In the first experiment, the germination of seeds

  20. Photoperiodism and crassulacean acid metabolism : I. Immunological and kinetic evidences for different patterns of phosphoenolpyruvate carboxylase isoforms in photoperiodically inducible and non-inducible Crassulacean acid metabolism plants.

    Science.gov (United States)

    Brulfert, J; Müller, D; Kluge, M; Queiroz, O

    1982-05-01

    Plants of Kalanchoe blossfeldiana v. Poelln. Tom Thumb and Sedum morganianum E. Walth. were grown under controlled photoperiodic conditions under either short or long days. Gaz exchange measurements confirmed that in K. blossfeldiana Crassulacean acid metabolism (CAM) was photoperiodically inducible and that S. morganianum performed CAM independently of photoperiod. With K. blossfeldiana, a comparison of catalytic and regulatory properties of phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) from short-day and long-day grown plants showed differences, but not with S. morganianum. Ouchterlony double diffusion tests and immunotitration experiments (using a S. morganianum PEPC antibody) established that CAM is induced in K. blossfeldiana-but not in S. morganianum-through the synthesis of a new PEPC isoform; this form shows an immunological behavior different from that prevailing under non-inductive conditions and can be considered as specific for CAM performance.

  1. Ciprofloxacin causes persister formation by inducing the TisB toxin in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Tobias Dörr

    2010-02-01

    Full Text Available Bacteria induce stress responses that protect the cell from lethal factors such as DNA-damaging agents. Bacterial populations also form persisters, dormant cells that are highly tolerant to antibiotics and play an important role in recalcitrance of biofilm infections. Stress response and dormancy appear to represent alternative strategies of cell survival. The mechanism of persister formation is unknown, but isolated persisters show increased levels of toxin/antitoxin (TA transcripts. We have found previously that one or more components of the SOS response induce persister formation after exposure to a DNA-damaging antibiotic. The SOS response induces several TA genes in Escherichia coli. Here, we show that a knockout of a particular SOS-TA locus, tisAB/istR, had a sharply decreased level of persisters tolerant to ciprofloxacin, an antibiotic that causes DNA damage. Step-wise administration of ciprofloxacin induced persister formation in a tisAB-dependent manner, and cells producing TisB toxin were tolerant to multiple antibiotics. TisB is a membrane peptide that was shown to decrease proton motive force and ATP levels, consistent with its role in forming dormant cells. These results suggest that a DNA damage-induced toxin controls production of multidrug tolerant cells and thus provide a model of persister formation.

  2. Transcriptional analysis of the unicellular, diazotrophic cyanobacterium Cyanothece sp. ATCC 51142 grown under short day/night cycles

    Energy Technology Data Exchange (ETDEWEB)

    Toepel, Jorg; McDermott, Jason E.; Summerfield, Tina; Sherman, Louis A.

    2009-06-01

    Cyanothece sp. strain ATCC 51142 is a unicellular, diazotrophic cyanobacterium that demonstrates extensive metabolic periodicities of photosynthesis, respiration and nitrogen fixation when grown under N2-fixing conditions. We have performed a global transcription analysis of this organism using 6 h light/dark cycles in order to determine the response of the cell to these conditions and to differentiate between diurnal and circadian regulated genes. In addition, we used a context-likelihood of relatedness (CLR) analysis with this data and those from two-day light/dark and light-dark plus continuous light experiments to better differentiate between diurnal and circadian regulated genes. Cyanothece sp. adapted in several ways to growth under short light/dark conditions. Nitrogen was fixed in every second dark period and only once in each 24 h period. Nitrogen fixation was strongly correlated to the energy status of the cells and glycogen breakdown and high respiration rates were necessary to provide appropriate energy and anoxic conditions for this process. We conclude that glycogen breakdown is a key regulatory step within these complex processes. Our results demonstrated that the main metabolic genes involved in photosynthesis, respiration, nitrogen fixation and central carbohydrate metabolism have strong (or total) circadian-regulated components. The short light/dark cycles enable us to identify transcriptional differences among the family of psbA genes, as well as the differing patterns of the hup genes, which follow the same pattern as nitrogenase genes, relative to the hox genes which displayed a diurnal, dark-dependent gene expression.

  3. Superação da dormência de cultivares de mirtileiro em ambiente protegido com cianamida hidrogenada e óleo mineral Dormancy breaking of blueberries cultivars in a protected environment with hydrogen cyanamide and mineral oil

    Directory of Open Access Journals (Sweden)

    Roberto Coletti

    2011-06-01

    Full Text Available O mirtileiro é uma frutífera de clima temperado que necessita de frio no outono/inverno. A insuficiência de frio pode provocar deficiente e desuniforme brotação e floração, com reflexos na produção. A pesquisa realizada na Universidade de Passo Fundo-RS, teve por objetivo estudar a superação da dormência de cultivares de mirtileiro (Georgiagem, Climax e Aliceblue em ambiente protegido, tratadas em 25-07-2007 com cianamida hidrogenada (CH, nas doses de 0,52% e 1,04% (1% e 2% do produto comercial Dormex®, com a adição de 0,5% de óleo mineral (OM, comparando com plantas sem tratamento. As plantas encontravam-se no terceiro ciclo vegetativo e no primeiro de produção. O plantio foi realizado em 2005, no espaçamento de 0,7 m x 2,0 m, com irrigação por gotejamento. De acordo com os resultados obtidos, a aplicação no final de julho de CH + OM concentrou e uniformizou a floração e antecipou a brotação das cvs. Georgiagem e Clímax. A cianamida hidrogenada, nas concentrações de 0,52% e 1,04% (1% e 2% de Dormex®, combinado com 0,5% de óleo mineral, não teve efeito na porcentagem de brotação, mas reduziu a produção, evidenciando efeitos fitotóxicos.Blueberry require chilling hours accumulation in the fall/winter. Insufficient cold accumulation can cause deficient and desuniform sprouting and blooming, with negative consequences on yield. The research conducted in Passo Fundo University, state of Rio Grande do Sul, had the objective of studying the dormancy breaking of blueberries cultivars (Georgiagem, Climax and Aliceblue under greenhouse conditions, submitted to treatments with hydrogen cyanamide (HC at the doses of 0.52% and 1.04% (1% and 2% of the commercial product Dormex®, with the addition of 0.5% of mineral oil (MO, and compare them to a control, without hydrogen cyanamide treatment. Planting was made in December 2005, at a 0.7 m x 2.0 m space, with drip irrigation. The plants were evaluated in the third

  4. Individuality, phenotypic differentiation, dormancy and ‘persistence’ in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology [version 2; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    Douglas Kell

    2015-09-01

    Full Text Available For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically ‘nonculturable’ on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as ‘persisters’. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one’s bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known. This dormancy (and resuscitation therefrom often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron might be of much therapeutic benefit.

  5. Superação da dormência de sementes de umbuzeiro (Spondias tuberosa, Arr. Câm. utilizando diferentes métodos Overcoming dormancy of 'umbuzeiro' seeds (Spondias tuberosa, Arr. Câm. by using different methods

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Nascimento Lopes

    2009-09-01

    difficulty of obtaining seedlings mainly depending on the dormancy of its seeds. Thus, the purpose of this study was to evaluate the seeds overcoming dormancy methods of Spondias Tuberosa to promote an increase in the rates of germination, uniformity and vigor of the seedlings. Two experiments were independently conducted. The treatments of the first experiments were: test, immersion of the seeds in water for 24 hours, immersion of the seeds in solution of gibberellic acid 1000 mg / L for 24 hours, scarification of seeds with sulfuric acid PA for 10 minutes and mechanical scarification of seeds. In the second experiment, the treatments consisted of planting the seeds with 0, 30, 60, 90, 120, 150, 180 and 210 days of storage in paper bags under laboratory conditions, at an average temperature of 22.5° C and relative humidity of 65%. In the first study it was found that there was a significant effect of the methods to seeds overcoming dormancy, concluding that the mechanical scarification is the best treatment, with an average germination rate in 60 days after planting 26.6%. In the second experiment, storage positively influenced the germination of seeds and seedlings vigor. The best results for uniformity and germination percentage (83% were obtained between 120 and 210 days of seeds storage, while for the length and fresh weight of root, between 120 and 150 days.

  6. Mechanism of fluridone-induced seed germination of cistanche tubulosa

    International Nuclear Information System (INIS)

    Chen, Q.L.; Tu, P.

    2016-01-01

    Our previous study disclosed that fluridone, a synthesis inhibitor of abscisic acid (ABA), could stimulate seed germination in the holoparasitic plant Cistanche tubulosa . Nonetheless, the underlying mechanisms have not been thoroughly elucidated. In the present study, an attempt was made to reveal the mechanism of fluridone breaking seed dormancy in C. tubulosa and to determine the contribution of hormones in this process. The ABA level in seeds initially decreased following fluridone treatment and was subsequently maintained at a concentration of 31 ng g/sup -1/ DW (dry weight) three days later. The contents of gibberellins (GAs) initially in creased and subsequently were maintained at a level of 40 ng g-1 DW after ten days. However, the increment of seed germination induced by fluridone was inhibited after the introduction of exogenous ABA or paclobutrazol (a synthesis inhibitor of GAs). Furthermore, inhibition from paclobutrazol was reversed by an additional treatment with exogenous GA3. When the ratio of endogenous GAs to ABA reached 4:3, C. tubulosa seeds initiated germination. By contrast, although the ratio of endogenous GAs to ABA content reached 2:1 by cold stratification, C. tubulosa seeds could not germinate unless exogenous GA3 was added. In summary, our current study revealed that (i) GAs and ABA play key roles for the seed germination of C. tubulosa , (ii) fluridone inhibited ABA biosynthesis but increased the concentration of GAs in seeds, and (iii) fluridone might initiate other processes associated with germination. (author)

  7. Rice breeding with induced mutations in France

    Energy Technology Data Exchange (ETDEWEB)

    Marie, R [Station d' Amelioration des Plantes, Institut National de Recherches Agronomiques, Montpellier (France)

    1970-03-01

    Mutation experiments with rice at Montpellier yielded strains with improved lodging resistance, grain size, maturing time, milling quality and other characters. The general performance of these mutant strains was tested in field trials. Further mutagenic treatments were made to improve the high-yielding short grain varieties with regard to grain quality and seed dormancy. (author)

  8. Cancer dormancy and cell signaling: Induction of p21waf1 initiated by membrane IgM engagement increases survival of B lymphoma cells

    Science.gov (United States)

    Marches, Radu; Hsueh, Robert; Uhr, Jonathan W.

    1999-01-01

    The p21WAF1 (p21) cyclin-dependent kinase inhibitor plays a major role in regulating cell cycle arrest. It was recently reported that the p53-independent elevation of p21 protein levels is essential in mediating the G1 arrest resulting from signal transduction events initiated by the crosslinking of membrane IgM on Daudi Burkitt lymphoma cells. Although the role of p21 in cell cycle regulation is well documented, there is little information concerning its role in antibody-mediated apoptosis. In the present study, we examined the involvement of p21 in the regulation of apoptosis by suppressing its induction in anti-IgM-treated Daudi cells through a p21 antisense expression construct approach. Reduction in induced p21 protein levels resulted in diminished G1 arrest and increased apoptosis. The increased susceptibility to anti-IgM-mediated apoptosis was associated with increased caspase-3-like activity and poly-(ADP)ribose polymerase cleavage. These data suggest that p21 may directly interfere with the caspase cascade, thus playing a dual role in regulating both cell cycle progression and apoptosis. PMID:10411940

  9. Temperaturas efetivas para a dormência da macieira(Malus domestica Borkh Effective temperatures for apple tree dormancy (Malus domestica Borkh

    Directory of Open Access Journals (Sweden)

    Gilberto Luiz Putti

    2003-08-01

    Full Text Available As cultivares de macieira exigem diferentes requerimentos em frio, ou seja, o total de horas abaixo de um limite de temperatura do ar, porém são poucas as informações sobre quais temperaturas são mais eficientes para superar a dormência. As cultivares de macieira Condesa, Baronesa, Daiane, Imperatriz, Fuji e Gala foram estudadas quanto à quantidade de frio e as temperaturas do ar para a indução da brotação. O delineamento experimental foi o inteiramente casualizado, no esquema fatorial, com seis cultivares, cinco níveis de unidades de frio ( 300; 600; 900; 1200 e 1500 UF e três temperaturas do ar ( 5; 10 e 15ºC. O tempo médio para brotação foi menor quando as cultivares foram submetidas a 1.500 unidades de frio, independentemente da temperatura. A temperatura efetiva para acumular frio varia com a cultivar, podendo chegar até 15ºC para cultivares de menor exigência em frio.Apple tree cultivars demand several requirements in cold but there's a little of information about what temperatures are the most efficient. Apple tree cultivars Condesa, Baronesa, Daiane, Imperatriz, Fuji and Gala were studied on quantity of cold and different temperatures for shooting inducement. Experimental delineation was full casualized on the factorial system, with six cultivars, five levels of cold unities and three temperatures. Average time for shooting was minor when the cultivars were exposed to 1,500 cold unities independently of the temperature. Effective temperature in order to accumulate cold ranges according to the cultivar, and it is able reaching until 15ºC in case of cultivar of lower demand in cold.

  10. Morphological changes induced by different doses of gamma irradiation in garlic sprouts

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, C.N. E-mail: pellegri@criba.edu.ar; Croci, C.A.; Orioli, G.A

    2000-03-01

    The objective of this work was to evaluate the effects of different doses of gamma rays applied in dormancy and post-dormancy on garlic bulbs in relation with some morphophysiological parameters. High (commercial) doses cause the complete inhibition of sprouting and mitosis (due to nuclear aberrations). Relatively low doses show no effects on bulbs but doses of 10 Gy applied in post-dormancy reduce sprouting and stop mitosis. This inhibition becomes noticeable from 150 days post-harvest onwards. Exogenous growth regulators can reverse these effects. Results may reinforce the good practice of radioinhibition processes in garlic. (author)0.

  11. Induced Seismicity

    Science.gov (United States)

    Keranen, Katie M.; Weingarten, Matthew

    2018-05-01

    The ability of fluid-generated subsurface stress changes to trigger earthquakes has long been recognized. However, the dramatic rise in the rate of human-induced earthquakes in the past decade has created abundant opportunities to study induced earthquakes and triggering processes. This review briefly summarizes early studies but focuses on results from induced earthquakes during the past 10 years related to fluid injection in petroleum fields. Study of these earthquakes has resulted in insights into physical processes and has identified knowledge gaps and future research directions. Induced earthquakes are challenging to identify using seismological methods, and faults and reefs strongly modulate spatial and temporal patterns of induced seismicity. However, the similarity of induced and natural seismicity provides an effective tool for studying earthquake processes. With continuing development of energy resources, increased interest in carbon sequestration, and construction of large dams, induced seismicity will continue to pose a hazard in coming years.

  12. Variações do conteúdo de glucose, frutose e sorbitol em gemas e ramos de macieira durante a dormência Variations of glucose, frutose and sorbitol content in buds and stems of apple tree during the dormancy period

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2006-12-01

    Full Text Available O objetivo deste trabalho foi determinar as variações do conteúdo de glucose, frutose e sorbitol em gemas e ramos de um ano de macieira durante o período de dormência. Os ramos da cultivar "Imperial Gala" foram coletados em Porto Amazonas-PR, em intervalos de 21 dias, de abril a agosto (19/04, 10/05, 31/05, 21/06, 12/07, 02/08 e 23/08, e receberam ou não tratamento com frio suplementar de 1.440 horas à temperatura de 4 a 7°C. As análises dos carboidratos foram realizadas em gemas e porções de ramos adjacentes às primeiras por cromatografia líquida de alta eficiência (HPLC. Ocorreu um acúmulo de glucose, frutose e sorbitol nas gemas de macieira durante a dormência. O acúmulo de glucose e frutose nos ramos aconteceu até o início de agosto quando, em seguida, houve redução, enquanto o sorbitol decresceu até junho e, em seguida, elevou-se até o final de agosto. O tratamento com frio ao longo da dormência modificou as variações dos conteúdos de carboidratos nas gemas e ramos de macieira.This research was aimed at evaluating the variations of glucose, frutose and sorbitol content in one year old buds and stems of apple trees during the dormancy period. The stems of cv. Imperial Gala were collected in Porto Amazonas, Parana State, Brazil, at intervals of 21 days from April to August (April 19th, May 10th, May 31st, June 21st, July 12th, August 2nd and August 23rd and were treated or not with 1,440 hours of chill (4 to 7°C. The carbohydrates were analysed in buds and stem tissues close to buds by high performance liquid chromatography (HPLC. There was an increase of glucose, frutose and sorbitol content in apple tree buds during the dormancy. An increase of glucose and frutose content in stems occured until August 2nd followed by a significative reduction, while the sorbitol content decreased until June 21st followed by an increase until August 31st. The chill treatment during the dormancy period modified the variations of

  13. Superação da dormência em sementes de visgueiro-do-igapó (Parkia discolor Overcoming seed dormancy in visgueiro-of-the-igapó (Parkia discolor

    Directory of Open Access Journals (Sweden)

    Sammy Aquino Pereira

    2010-03-01

    proximal portion; scraping at the proximal and distal portions; perforation of the husk with a soldering-iron; and perforation by pyrography. In the second experiment, with a completely randomized design and factorial 2 (heat: dry and wet x 4 (temperature: 40ºC, 50ºC, 60ºC and 70ºC x 5 (period of conditioning: 6, 16, 24, 30 and 48 hours, with three repetitions. The clipping or scraping of the seeds in the proximal portion and proximal and distal portions allowed faster imbibition of the seeds (143-163% in three days and half, and consequently, better germination (98-100% in four days, germination speed rate (1,351-1,460 and average time of germination (3 days. The pre-treatment with heat (wet and dry, under different temperatures and different conditioning periods did not overcome the dormancy of P. discolor seeds.

  14. Métodos para quebra de dormência de unidades de dispersão de Zizyphus joazeiro Mart. (Rhamnaceae Methods for dormancy breaking of Zizyphus joazeiro Mart. dispersal units

    Directory of Open Access Journals (Sweden)

    Edna Ursulino Alves

    2008-06-01

    Full Text Available O Z. joazeiro é uma espécie florestal de grande importância socioeconômica para a Região Nordeste do Brasil e apresenta dificuldades na germinação das unidades de dispersão, causada pela impermeabilidade à água. Este estudo avaliou tratamentos pré-germinativos de superação de dormência de unidades de dispersão de Z. joazeiro. O experimento foi conduzido em casa de vegetação, no Centro de Ciências Agrárias da Universidade Federal da Paraíba, em Areia, PB, Brasil. Os tratamentos consistiram em: testemunha (unidades de dispersão intactas, escarificação mecânica com lixa d'água, imersão em água, à temperatura ambiente, por 24, 48, 72, 96 e 120 h, imersão em água à temperatura de 70 ºC, por 3 min, e imersão em ácido sulfúrico concentrado por 30, 60, 90, 120 e 150 min. As variáveis avaliadas foram porcentagem de emergência, primeira contagem e velocidade de emergência, comprimento e massa seca de plantas. Os tratamentos que propiciaram máxima emergência de plântulas de Z. joazeiro foram imersão de unidades de dispersão em água fria por 48 h, imersão em água a 70 ºC por 3 min e escarificação manual com lixa, por superar a dureza tegumentar das unidades de dispersão dessa espécie.Z. joazeiro is a forest species of great socioeconomic importance for the Brazilian Northeast region, but of difficult germination caused by the water impermeability of dispersal units. The present study evaluated pre-germinative treatments for overcoming dormancy in Zizyphus joazeiro seeds. The experiment was carried out in greenhouse conditions at Centro de Ciencias Agrárias, Universidade Federal da Paraíba, Areia-PB, Brazil. The treatments were as follow: control (intact dispersal units, mechanical scarification with sandpaper, immersion in water at room temperature for 24, 48, 72, 96 and 120 hours, immersion in water at 70 C for three minutes and, immersion in concentrated sulfuric acid for 30, 60, 90, 120 and 150 minutes

  15. Identifying ECM Mediators of Tumor Cell Dormancy

    National Research Council Canada - National Science Library

    Schedin, Pepper

    2007-01-01

    .... The ECM preparations have been subjected to LCMS and MALDI-TOF mass spec. Due to technical difficulties also developed two in vitro models to investigate the effects of tamoxifen on mammary stroma...

  16. 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

  17. Dormancy cycling in seeds: mechanisms and regulation

    NARCIS (Netherlands)

    Claessens, S.M.C.

    2012-01-01

    The life cycle of most plants starts, and ends, at the seed stage. In most species mature seeds are shed and dispersed on the ground. At this stage of its life cycle the seed may be dormant and will, by definition, not germinate under favourable conditions (Bewley, 1997).

    Seasonal

  18. Buried Alive! An Investigation of Plant Dormancy

    Science.gov (United States)

    Allen, Ashley J.; Balschweid, Mark; Hammond, Paul; Henderson, Brian; Johnson, Peggy A.; Kite, Abigayle; Martin, Stephanie

    2004-01-01

    In this investigation, pairs of upper elementary students test germination percentage using seeds of Indian corn ("Zea mays"), scarlet runner beans ("Phaseolus coccineus"), and the prairie cup-plant ("Silphium perfoliatum") grown on rolled, damp paper towels. The pairs compare seeds that have been stratified, a simulation of overwintering and…

  19. ``Sleeping with the enemy''—predator-induced diapause in a mite

    Science.gov (United States)

    Kroon, Annemarie; Veenendaal, René L.; Bruin, Jan; Egas, Martijn; Sabelis, Maurice W.

    2008-12-01

    Diapause in arthropods is a physiological state of dormancy that is generally thought to promote survival during harsh seasons and dispersal, but it may also serve to avoid predation in space and time. Here, we show that predation-related odours induce diapause in female adult spider mites. We argue that this response allows them to move into an area where they are free of enemies, yet forced to survive without food. Spider mites are specialised leaf feeders, but—in late summer—they experience severe predation on leaves. Hence, they face a dilemma: to stay on the leaf and risk being eaten or to move away from the leaf and risk death from starvation and thirst. Female two-spotted spider mites solve this dilemma by dramatically changing their physiology when exposed to predation-associated cues. This allows them to disperse away from leaves and to survive in winter refuges in the bark of trees or in the soil. We conclude that the mere presence of predation-associated cues causes some herbivorous mites to seek refuge, thereby retarding the growth rate of the population as a whole: a trait-mediated indirect effect that may have consequences for the stability of predator prey systems and for ecosystem structure.

  20. Micro-environmental mechanical stress controls tumor spheroid size and morphology by suppressing proliferation and inducing apoptosis in cancer cells.

    Directory of Open Access Journals (Sweden)

    Gang Cheng

    Full Text Available Compressive mechanical stress produced during growth in a confining matrix limits the size of tumor spheroids, but little is known about the dynamics of stress accumulation, how the stress affects cancer cell phenotype, or the molecular pathways involved.We co-embedded single cancer cells with fluorescent micro-beads in agarose gels and, using confocal microscopy, recorded the 3D distribution of micro-beads surrounding growing spheroids. The change in micro-bead density was then converted to strain in the gel, from which we estimated the spatial distribution of compressive stress around the spheroids. We found a strong correlation between the peri-spheroid solid stress distribution and spheroid shape, a result of the suppression of cell proliferation and induction of apoptotic cell death in regions of high mechanical stress. By compressing spheroids consisting of cancer cells overexpressing anti-apoptotic genes, we demonstrate that mechanical stress-induced apoptosis occurs via the mitochondrial pathway.Our results provide detailed, quantitative insight into the role of micro-environmental mechanical stress in tumor spheroid growth dynamics, and suggest how tumors grow in confined locations where the level of solid stress becomes high. An important implication is that apoptosis via the mitochondrial pathway, induced by compressive stress, may be involved in tumor dormancy, in which tumor growth is held in check by a balance of apoptosis and proliferation.

  1. Quebra de dormência de pereira 'Hosui' com uso de óleo mineral em dois tipos de condução Dormancy broken of 'Hosui' pear trees with mineral oil in two training systems

    Directory of Open Access Journals (Sweden)

    Odirlei Raimundo de Oliveira

    2008-06-01

    , need to have their dormancy broken by artificial means. In order to minimize such problem, an experiment was conducted in a 4-year-old 'Hosui' pear (Pyrus pyrifolia with 4.0 x 4.0m tree spacing orchard, at the Canguiri Station, in Pinhais-PR (latitude 25º25'S, longitude 49º08' and altitude of 920m, pertaining to the Federal University of Parana, in which accumulation of 141 chilling hours under 7.2ºC was reached during the 2005 winter. Treatments were applied when plants were at the A1 phenological stage (bud swelling, using a completely randomized factorial design with 4 replications in a 2x4x7 factorial scheme in which two types of tree training, vase or central leader, three mineral oil concentrations, 4, 6 or 8%, and a control applied from August to November 2005, and seven weekly performed evaluations based on the number of buds at pre-budding stage as well as broken and dead buds in four previously selected horizontally inclined 1-year-old stems per tree were tested. Obtained results showed that application of mineral oil at 4, 6 and 8% anticipated bud break compared to the control and enhanced bud break percentage in both training systems, being the concentrations of 6% and 8% more effective in anticipating bud break than 4%. The percentage of bud break at the 84th day after mineral oil application did not differ between the two training systems, i.e. vase and central leader.

  2. Métodos de superação de dormência em sementes de croada (Mouriri elliptica Mart Dormancy breaking methods in croada (Mouriri elliptica Mart seeds

    Directory of Open Access Journals (Sweden)

    Jaqueline Martins Vasconcelos

    2010-10-01

    Full Text Available Sementes de croada (Mouriri elliptica Mart. Melastomataceae, espécie frutífera nativa do cerrado, foram submetidas aos seguintes tratamentos, visando a superação de dormência: pré-resfriamento a 5° C por 7 dias; pré-aquecimento em estufa com circulação de ar a 40º C por 7 dias; escarificação química em ácido sulfúrico concentrado por 5 e 15 minutos; imersão em água fervente por 5 e 15 minutos; imersão em ácido giberélico a 100 e 200 mg L-1 por 48 horas; imersão em água destilada por 24 e 48 horas; escarificação mecânica com lixa nº 80 na parte superior e oposta ao eixo embrionário e testemunha (sementes sem tratamento prévio. Quatro repetições de quinze sementes foram colocadas para germinar sobre papel umedecido com água destilada ou nitrato de potássio a 0,2%, em temperatura de 30º C em presença de luz. Foram realizadas contagens diárias do 2º dia após a implantação do experimento até a estabilização da porcentagem de germinação, que acorreu no 60º dia. A germinação foi mais rápida em sementes pré-embebidas em ácido giberélico (em substrato umedecido com água ou com solução de nitrato de potássio 0,2%, pré-embebidas em água por 24 horas, em substrato umedecido com água, e pré-embebidas em água por 48 horas ou escarificadas mecanicamente e colocadas para germinar em substrato umedecido com água. Taxas de germinação mais elevadas ocorreram em sementes pré-embebidas em ácido giberélico a 100 ou 200 mg L-1, em substrato umedecido com solução de nitrato de potássio 0,2%.Croada seeds (Mouriri elliptica Mart. Melastomataceae, a fruit-bearing species native of the cerrado (savannah-like vegetation, were submitted to the following dormancy breaking methods: pre-cooling at 5° C for 7 days; pre-heating in a oven air circualtion at 40º C for 7 days; chemical escarification in concentrated sulfuric acid for 5 and 15 min; soaking in boiling water for 5 and 15 min; soaking in gibbereli

  3. Cancer Stem Cells and stress induced evolution - understanding the ...

    Indian Academy of Sciences (India)

    Dr S Bapat

    2015-11-08

    Nov 8, 2015 ... Most therapies fail to consider differential drug sensitivities of various cells in a tumor. (Tumor Cell Heterogeneity). • Drug refractory behaviour of tumor cells may arise due to either –. - Intrinsic drug resistance mechanisms (Molecular Heterogeneity). - Cell dormancy / reversible quiescence (Cancer stem ...

  4. Superação de dormência na qualidade de sementes e mudas: influência na produção de Senna multijuga (L. C. Rich. Irwin & Barneby Overcoming of dormancy in the quality of seeds and seedlings: influence in the production of Senna multijuga (L.C. Rich. Irwin & barneby

    Directory of Open Access Journals (Sweden)

    Graziela Piveta

    2010-01-01

    Full Text Available O objetivo deste trabalho foi determinar a qualidade fisiológica e sanitária de sementes de Senna multijuga(L. C. Rich. Irwin & Barneby relacionada aos métodos de superação de dormência e à interferência na produção de mudas. As sementes foram submetidas aos seguintes métodos: imersão em água fervente, as sementes foram imersas em água, com temperatura de 100°C, até esfriar, por 24 horas; escarificação ácida, onde as sementes foram imersas em ácido sulfúrico (H2SO4 a 90%, por 10 e 20 minutos, e testemunha (sem tratamento. Foram realizados os testes de sanidade, germinação, tetrazólio e avaliação da qualidade das mudas. O delineamento experimental foi inteiramente casualizado. Para a avaliação da germinação foi utilizado um esquema fatorial (4 X 2, com quatro métodos de superação de dormência X dois fotoperíodos, para os substratos rolo-de-papel e vermiculita. A escarificação ácida constituiu-se no método mais eficiente para a superação da dormência das sementes de Senna multijuga. Penicillium sp. e Aspergillus sp. tiveram sua incidência aumentada quando o tegumento foi danificado pela escarificação ácida por 20 minutos. O controle de Fusarium spp. aumentou gradativamente com o aumento do tempo de exposição ao ácido sulfúrico.The objective of this work was to determine the physiological and sanitary quality of Senna multijugaseeds related to the methods of dormancy overcoming and the influence on the seedlings quality. The seeds had been submitted to the following methods :immersion in water fervent, the seeds had been immersed in water, at 100°C, until cooling for 24 hours; acid escarification, where the seeds had been immersed in sulfuric acid (H2SO4 90%, for 10 and 20 minutes, and control (without treatment. The tests of sanity, germination and tetrazolium had been carried through, and were evaluated the quality of the seedlings. For the germination of the evaluation an factorial project was

  5. Dinâmica da dormência de gemas de dois anos de macieira 'Imperial Gala' em região de baixa ocorrência de frio Dormancy dynamics of two year old buds of 'Imperial Gala' apple tree in a region of low chill occurence

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2004-12-01

    Full Text Available O objetivo deste trabalho foi determinar a dinâmica da dormência de gemas em ramos de dois anos de macieira 'Imperial Gala' com ou sem frio suplementar durante o outono e inverno, cultivadas em Porto Amazonas - PR, região de baixa ocorrência de frio. Os ramos foram coletados em intervalos de 21 dias, de abril a agosto (19-04, 10-05, 31-05, 21-06, 12-07, 02-08 e 23-08 e receberam ou não tratamento com frio suplementar de 1.440 horas, à temperatura de 4 a 7° C. A avaliação da dormência foi realizada pelo teste biológico de estacas de nós isolados (temperatura de 25° C e fotoperíodo de 16 horas por meio dos parâmetros: tempo médio para brotação (TMB, velocidade de brotação (VB, taxa final de brotação (TF, taxa de brotações vigorosas (TBV e tempo médio para aparecimento de folhas abertas (TMFA. A dormência mais intensa de gemas de dois anos ocorre no final de maio, com oscilações até o início de agosto. A aplicação de 1.440 horas de frio suplementar de 4 a 7° C altera a dinâmica da dormência das gemas de dois anos, reduzindo o seu tempo médio de brotação. Uma vez propiciada a brotação de gemas não-dormentes de dois anos, as mesmas possuem boa capacidade para se desenvolver.This work aims to evaluate the dormancy dynamics of two year old apple tree buds with or without supplementary chill during autumn and winter, in a region of low chill occurence. The stems were collected in Porto Amazonas, Parana State, Brazil, at intervals of 21 days from April to August (April 19th, May 10th, May 31st, June 21st, July 12th, August 2nd and August 23rd and were either treated or not with 1,440 hours of chill (4 to 7° C. The evaluation of dormancy was observed through the biological test of single node cuttings under controlled conditions (25° C and long days of 16 hours by the following parameters: average time for budburst (TMB, velocity of budburst (VB, final rate of budburst (TF, rate of vigorous budburst (TBV and

  6. Inducing autophagy

    DEFF Research Database (Denmark)

    Harder, Lea M; Bunkenborg, Jakob; Andersen, Jens S.

    2014-01-01

    catabolism, which has recently been found to induce autophagy in an MTOR independent way and support cancer cell survival. In this study, quantitative phosphoproteomics was applied to investigate the initial signaling events linking ammonia to the induction of autophagy. The MTOR inhibitor rapamycin was used...... as a reference treatment to emphasize the differences between an MTOR-dependent and -independent autophagy-induction. By this means 5901 phosphosites were identified of which 626 were treatment-specific regulated and 175 were coregulated. Investigation of the ammonia-specific regulated sites supported that MTOR...

  7. Adrenal hormones mediate melatonin-induced increases in aggression in male Siberian hamsters (Phodopus sungorus).

    Science.gov (United States)

    Demas, Gregory E; Polacek, Kelly M; Durazzo, Alfredo; Jasnow, Aaron M

    2004-12-01

    Among the suite of seasonal adaptations displayed by nontropical rodents, some species demonstrate increased territorial aggression in short compared with long day lengths despite basal levels of testosterone. The precise physiological mechanisms mediating seasonal changes in aggression, however, remain largely unknown. The goal of the present study was to examine the role of melatonin, as well as adrenal hormones, in the regulation of seasonal aggression in male Siberian hamsters (Phodopus sungorus). In Experiment 1, male Siberian hamsters received either daily (s.c.) injections of melatonin (15 microg/day) or saline 2 h before lights out for 10 consecutive days. In Experiment 2, hamsters received adrenal demedullations (ADMEDx), whereas in Experiment 3 animals received adrenalectomies (ADx); control animals in both experiments received sham surgeries. Animals in both experiments subsequently received daily injections of melatonin or vehicle as in Experiment 1. Animals in all experiments were tested using a resident-intruder model of aggression. In Experiment 1, exogenous melatonin treatment increased aggression compared with control hamsters. In Experiment 2, ADMEDx had no effect on melatonin-induced aggression. In Experiment 3, the melatonin-induced increase in aggression was significantly attenuated by ADx. Collectively, the results of the present study demonstrate that short day-like patterns of melatonin increase aggression in male Siberian hamsters and suggest that increased aggression is due, in part, to changes in adrenocortical steroids.

  8. A darklight transition triggers expression of the floral promoter CrFTL1 and downregulates CONSTANS-like genes in a short-day plant Chenopodium rubrum

    Czech Academy of Sciences Publication Activity Database

    Drabešová, Jana; Cháb, David; Kolář, Jan; Haškovcová, Kateřina; Štorchová, Helena

    2014-01-01

    Roč. 65, č. 8 (2014), s. 2137-2146 ISSN 0022-0957 R&D Projects: GA ČR GA522/05/0300; GA ČR(CZ) GAP506/12/1359 Institutional support: RVO:61389030 Keywords : Chenopodium rubrum * CONSTANS-like * flowering Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.526, year: 2014

  9. Genomic Analysis Reveals Contrasting PIFq Contribution to Diurnal Rhythmic Gene Expression in PIF-Induced and -Repressed Genes.

    Science.gov (United States)

    Martin, Guiomar; Soy, Judit; Monte, Elena

    2016-01-01

    Members of the PIF quartet (PIFq; PIF1, PIF3, PIF4, and PIF5) collectively contribute to induce growth in Arabidopsis seedlings under short day (SD) conditions, specifically promoting elongation at dawn. Their action involves the direct regulation of growth-related and hormone-associated genes. However, a comprehensive definition of the PIFq-regulated transcriptome under SD is still lacking. We have recently shown that SD and free-running (LL) conditions correspond to "growth" and "no growth" conditions, respectively, correlating with greater abundance of PIF protein in SD. Here, we present a genomic analysis whereby we first define SD-regulated genes at dawn compared to LL in the wild type, followed by identification of those SD-regulated genes whose expression depends on the presence of PIFq. By using this sequential strategy, we have identified 349 PIF/SD-regulated genes, approximately 55% induced and 42% repressed by both SD and PIFq. Comparison with available databases indicates that PIF/SD-induced and PIF/SD-repressed sets are differently phased at dawn and mid-morning, respectively. In addition, we found that whereas rhythmicity of the PIF/SD-induced gene set is lost in LL, most PIF/SD-repressed genes keep their rhythmicity in LL, suggesting differential regulation of both gene sets by the circadian clock. Moreover, we also uncovered distinct overrepresented functions in the induced and repressed gene sets, in accord with previous studies in other examined PIF-regulated processes. Interestingly, promoter analyses showed that, whereas PIF/SD-induced genes are enriched in direct PIF targets, PIF/SD-repressed genes are mostly indirectly regulated by the PIFs and might be more enriched in ABA-regulated genes.

  10. Dormancy breaking in Mauritia flexuosa seeds by using mechanical scarification and soaking = Superação de dormência em sementes de buriti por meio da escarificação mecânica e embebição

    Directory of Open Access Journals (Sweden)

    Alexsander Seleguini

    2012-12-01

    Full Text Available The majority of Arecaceae species presents difficulties to germinate, even under appropriate conditions, complicating the seedlings production process. This study aimed at evaluating the influence of seed scarification and soaking in the emergence and development of Mauritia flexuosa seedlings. The treatments consisted of a combination of seed soaking and scarification methods, in a completely randomized design, in a 2 x 3 + 1 factorial scheme, with five replications. Seeds with and without scarification, combined with soaking methods (not soaked seeds and seeds soaked for 30 days, with and without daily water renewal, plus an additional treatment, where the seeds were scarified after soaking for 30 days, were tested. The seedlingemergence up to 146 days after sowing (d.a.s. was evaluated, as well as the emergence rate index (46 and 146 d.a.s. and growth components (146 d.a.s.. The results were submitted to the variance analysis (F test and means compared by using the Tukey test, at 5%. It was possible to conclude that the Mauritia flexuosa seeds presented tegument dormancy. The seed scarification increased the germination rate, however, it contributed to increase the seeds mortality rate. The soaking of nonscarified seeds for 30 days, with daily water renewal, improved the potential for seed germination. The mechanical scarification, without or after soaking the seeds in water, increased the Mauritia flexuosa seedlings mortality rate, and it is not, therefore, a suitable method for dormancy breaking. = A maioria das espécies de Arecaceae apresenta dificuldades para germinar, mesmo sob condições adequadas, dificultando a produção de mudas. Objetivou-se, com este trabalho, avaliar a influência da escarificação e embebição de sementes na emergência e desenvolvimento de mudas de buritizeiro. Os tratamentos foram compostos pela combinação de métodos de embebição e escarificação de sementes, adotando-se o delineamento inteiramente

  11. Ácido sulfúrico superação da dormência de unidade de dispersão de juazeiro (Zizyphus joazeiro Mart. The use of sulfuric acid to break dispersal unit dormancy of Zizyphus joazeiro Mart.

    Directory of Open Access Journals (Sweden)

    Edna Ursulino Alves

    2006-04-01

    Full Text Available O Zizyphus joazeiro Mart. apresenta redução sensível no número de indivíduos em seu ambiente natural devido, entre outras causas, à ocorrência de dormência exógena da unidade de dispersão (impermeabilidade à água. Avaliou-se o efeito do período de imersão (0, 30, 60, 90, 120 e 150 min dessas unidades de dispersão, em ácido sulfúrico (98 %, na emergência e vigor das sementes (primeira contagem, índice de velocidade e tempo médio de emergência, altura e massa seca de plantas. O experimento foi realizado em casa de vegetação, utilizando-se o delineamento inteiramente ao acaso, com seis tratamentos e quatro repetições. O pré-condicionamento das unidades de dispersão de Zizyphus joazeiro Mart., em ácido sulfúrico concentrado, mostrou-se eficiente na superação da dormência dessa espécie, promovendo aumento na porcentagem e velocidade de emergência, primeira contagem de emergência, na altura e massa seca de plantas e redução no tempo médio para emergência. A eficiência do tratamento químico com ácido sulfúrico concentrado depende do período de imersão, sendo a faixa entre 74 e 115 min mais adequada para proporcionar maiores porcentagens de emergência e de vigor.Zizyphus joazeiro Mart. trees have been declining in number in their natural habitat due to, among other reasons, the occurrence of dormancy of dispersal units (water impermeability. The effect of the immersion time (0, 30, 60, 90, 120 and 150 minutes of Zizyphus joazeiro Mart. dispersal units in concentrated sulfuric acid (95-98 % was evaluated through the emergency and vigor (first count, speed index and mean emergence time, plant height and dry matter weight. The experiment was performed under greenhouse conditions, with a completely randomized experimental design, six treatments and four replications. The pre-conditioning of Zizyphus joazeiro Mart. dispersal units with immersion in concentrated sulfuric acid was efficient for breaking the seed

  12. Dinâmica da dormência de gemas de videira e quivizeiro em região de baixa ocorrência de frio Dormancy dynamics of grape and kiwi tree buds in a region of low chill occurrence

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Biasi

    2010-12-01

    Full Text Available O objetivo desta pesquisa foi determinar a dinâmica da dormência de gemas de videira cv. Niagara Branca e de quivizeiro cv. Bruno, em região de baixa ocorrência de frio. Os experimentos foram realizados nos anos de 2007 e 2008, com coletas de ramos a cada duas semanas, em pomares localizados em Pinhais-PR. Na última coleta, um grupo adicional de ramos foi coletado e mantido em refrigerador a temperatura de 4 a 7º C, por 1.440 horas. A avaliação da dormência foi realizada por meio do teste biológico de estacas de nós isolados em sala de crescimento, à temperatura de 25º C e fotoperíodo de 16 horas. Foi realizada a quantificação de horas de frio (HF e de unidades de frio (UF ocorridas na região. As duas espécies foram avaliadas como experimentos distintos. O delineamento experimental adotado foi o completamente casualizado, com doze tratamentos em 2007 e onze tratamentos em 2008, ambos com quatro repetições e dez estacas por unidade experimental. A endodormência de gemas de quivizeiro 'Bruno' instala-se a partir de abril e atinge maior intensidade do final de maio à segunda metade de junho. A saída da endodormência pode ocorrer naturalmente até o fim de agosto, mas com variações entre os anos. A endodormência de gemas de videira 'Niagara Branca' instala-se em abril e mantém-se intensa até maio. A saída natural da endodormência ocorre da metade de agosto ao início de setembro.The objective of this work was to evaluate the dormancy dynamic of 'Niagara Branca' grape and 'Bruno' kiwi tree buds in a region of low chill occurrence. The experiments were carried out in 2007 and 2008 through cut branches every two weeks in orchards in Pinhais-PR. In the last date, an additional group of stems was collected and maintained in a refrigerator at temperature of 4 to 7º C by 1440 hours. The evaluation of dormancy was observed by the biological test of single node cuttings into a growth room with temperature of 25º C and

  13. Aspectos biométricos de frutos e sementes, grau de umidade e superação de dormência de jatobá = Biometric aspects of fruit and seeds, moisture content and overcoming of the dormancy in jatoba

    Directory of Open Access Journals (Sweden)

    Leonaldo Alves de Andrade

    2010-04-01

    Full Text Available Este trabalho objetivou caracterizar biometricamente sementes e frutos de Hymenaea courbaril L. e determinar o grau de umidade, bem como avaliar diferentes tratamentos de superação de dormência. Foram determinados a biometria, a massa de frutos e sementes e o número de sementes por fruto. As sementes foram submetidas aos seguintescortes: 1-testemunha, sem escarificação ou corte; 2-escarificação em três faces; 3-corte ao meio e 4-corte em quatro partes. Avaliou-se também o percentual de emergência, o IVE, o comprimento da parte aérea e da raiz de plântulas. Para isso, as sementes foram submetidasà superação de dormência, com e sem embebição em água, pelos seguintes tratamentos: Iescarificação do lado oposto ao hilo; II-escarificação em uma lateral; III-escarificação em duas laterais; IV-escarificação em uma lateral e no lado oposto ao hilo; V-escarificação em duas laterais e no lado oposto ao hilo; VI-Testemunha, sem escarificação. O comprimento, a largura, o diâmetro e a massa média dos frutos foram 115,7 mm; 62,18 mm; 43,8 mm e 183,85 g, respectivamente. Para a determinação da umidade, deve-se cortar as sementes em pelo menos duas partes. A escarificação, independentemente da posição na semente, com ou sem embebição em água, possibilita maior qualidade fisiológica.This study aimed to characterize biometrical seeds and fruits ofHymenaea courbaril L., determine the moisture content and assess different treatments to overcome dormancy. Fruit biometry, mass of fruits and seeds, and the number of seeds per fruit were determined. The seeds were submitted to the following treatments: 1-control, without cutting or scarification, 2-scarification on three sides, 3-cut in half and 4-cut in four parts. The percentage of emergence, emergence speed index, length of the buds and root of seedlings werealso evaluated. So, the seeds were submitted to overcome dormancy, with and without soaking in water, represented by

  14. Exercise-Induced Asthma

    Science.gov (United States)

    ... Videos for Educators Search English Español Exercise-Induced Asthma KidsHealth / For Parents / Exercise-Induced Asthma What's in ... Exercise-Induced Asthma Print What Is Exercise-Induced Asthma? Most kids and teens with asthma have symptoms ...

  15. Dinâmica do conteúdo de monossacarídeos em gemas e ramos de dois anos de macieira durante a endodormência Dynamics of monosaccharides content in two year old buds and stems of apple tree during the dormancy period

    Directory of Open Access Journals (Sweden)

    Ruy Inacio Neiva de Carvalho

    2006-08-01

    Full Text Available O objetivo do trabalho foi determinar as variações do conteúdo de glucose, frutose e sorbitol em gemas e ramos de dois anos de macieira que receberam ou não frio suplementar durante o período de dormência. Os ramos da cultivar Imperial Gala foram coletados em Porto Amazonas-PR, região de baixa ocorrência de frio, em intervalos de 21 dias, de abril a agosto, e receberam ou não tratamento com frio suplementar de 1.440 horas, à temperatura de 4 a 7°C. As análises dos monossacarídeos foram realizadas em gemas e porções de ramos adjacentes a elas por cromatografia líquida de alta eficiência (HPLC. Houve acúmulo de glucose e frutose em gemas de macieira de abril a agosto, e este aumento foi estimulado pelo tratamento com 1.440 horas de frio. O conteúdo de glucose e frutose nos ramos adjacentes às gemas elevou-se de abril ao início de agosto, com posterior queda no final de agosto e o tratamento com frio antecipou esta dinâmica. O conteúdo de sorbitol em gemas e ramos de macieira oscilou de abril a agosto, e sua dinâmica foi alterada pelo frio.The objective of this work was to evaluate the variation of glucose, fructose and sorbitol content in two year old buds and stems of apple trees during the dormancy period. Stems of cv. Imperial Gala were collected in Porto Amazonas, Parana State, Brazil, a region of low chill occurence, at intervals of 21 days from April to August and were treated or not with 1,440 hours of chill (4 to 7°C. The monosaccharides were analysed in buds and stem tissues close to buds by high performance liquid chromatography (HPLC. There was an increase of glucose and fructose content in buds from April to August and it was stimulated by the chill treatment. The glucose and fructose content in stems increased from April to August 2nd followed by a reduction in August 23rd and the chill treatment advanced this dynamics. The sorbitol content in buds and stems of apple tree oscillated from April to August and

  16. A Virus-Induced Assay for Functional Dissection and Analysis of Monocot and Dicot Flowering Time Genes.

    Science.gov (United States)

    Qin, Cheng; Chen, Weiwei; Shen, Jiajia; Cheng, Linming; Akande, Femi; Zhang, Ke; Yuan, Chen; Li, Chunyang; Zhang, Pengcheng; Shi, Nongnong; Cheng, Qi; Liu, Yule; Jackson, Stephen; Hong, Yiguo

    2017-06-01

    Virus-induced flowering (VIF) uses virus vectors to express Flowering Locus T ( FT ) to induce flowering in plants. This approach has recently attracted wide interest for its practical applications in accelerating breeding in crops and woody fruit trees. However, the insight into VIF and its potential as a powerful tool for dissecting florigenic proteins remained to be elucidated. Here, we describe the mechanism and further applications of Potato virus X (PVX)-based VIF in the short-day Nicotiana tabacum cultivar Maryland Mammoth. Ectopic delivery of Arabidopsis ( Arabidopsis thaliana ) AtFT by PVX/AtFT did not induce the expression of the endogenous FT ortholog NtFT4 ; however, it was sufficient to trigger flowering in Maryland Mammoth plants grown under noninductive long-day conditions. Infected tobacco plants developed no systemic symptoms, and the PVX-based VIF did not cause transgenerational flowering. We showed that the PVX-based VIF is a much more rapid method to examine the impacts of single amino acid mutations on AtFT for floral induction than making individual transgenic Arabidopsis lines for each mutation. We also used the PVX-based VIF to demonstrate that adding a His- or FLAG-tag to the N or C terminus of AtFT could affect its florigenic activity and that this system can be applied to assay the function of FT genes from heterologous species, including tomato ( Solanum lycopersicum ) SFT and rice ( Oryza sativa ) Hd3a Thus, the PVX-based VIF represents a simple and efficient system to identify individual amino acids that are essential for FT-mediated floral induction and to test the ability of mono- and dicotyledonous FT genes and FT fusion proteins to induce flowering. © 2017 American Society of Plant Biologists. All Rights Reserved.

  17. Drug-induced thrombocytopenia

    DEFF Research Database (Denmark)

    Pedersen-Bjergaard, U; Andersen, M; Hansen, P B

    1997-01-01

    induced by non-cytotoxic drugs is characterised by heterogeneous clinical picture and recovery is generally rapid. Although corticosteroids seem inefficient, we still recommend that severe symptomatic cases of drug-induced thrombocytopenia are treated as idiopathic thrombocytopenic purpura due...

  18. Photoperiod induced obesity in the Brandt's vole (Lasiopodomys brandtii: a model of ‘healthy obesity’?

    Directory of Open Access Journals (Sweden)

    Xin-Yu Liu

    2016-11-01

    Full Text Available Brandt's voles have an annual cycle of body weight and adiposity. These changes can be induced in the laboratory by manipulation of photoperiod. In the present study, male captive-bred Brandt's voles aged 35 days were acclimated to a short day (SD photoperiod (8L:16D for 70 days. A subgroup of individuals (n=16 were implanted with transmitters to monitor physical activity and body temperature. They were then randomly allocated into long day (LD=16L:8D (n=19, 8 with transmitters and SD (n=18, 8 with transmitters groups for an additional 70 days. We monitored aspects of energy balance, glucose and insulin tolerance (GTT and ITT, body composition and organ fat content after exposure to the different photoperiods. LD voles increased in weight for 35 days and then re-established stability at a higher level. At the end of the experiment LD-exposed voles had greater white adipose tissue mass than SD voles (P=0.003. During weight gain they did not differ in their food intake or digestive efficiency; however, daily energy expenditure was significantly reduced in the LD compared with SD animals (ANCOVA, P<0.05 and there was a trend to reduced resting metabolic rate RMR (P=0.075. Physical activity levels were unchanged. Despite different levels of fat storage, the GTT and ITT responses of SD and LD voles were not significantly different, and these traits were not correlated to body fatness. Hence, the photoperiod-induced obesity was independent on disruptions to glucose homeostasis, indicating a potential adaptive decoupling of these states in evolutionary time. Fat content in both the liver and muscle showed no significant difference between LD and SD animals. How voles overcome the common negative aspects of fat storage might make them a useful model for understanding the phenomenon of ‘healthy obesity’.

  19. Substratos alternativos e métodos de quebra de dormência para produção de mudas de canafístula Alternative substrates and methods of breaking dormancy for the production of canafístula seedlings

    Directory of Open Access Journals (Sweden)

    Tiago Reis Dutra

    2013-02-01

    Full Text Available O objetivo deste estudo foi avaliar o efeito de diferentes métodos de quebra de dormência e o uso do bagaço de cana para composição de substratos alternativos, constituídos a partir da mistura de um substrato comercial, na produção de mudas de canafístula (Peltophorum dubium (Sprengel Taubert. O experimento foi conduzido em delineamento de blocos casualizados, no esquema fatorial 5 x 4, sendo cinco substratos, Bioplant®; 75% Bioplant® + 25% Bagaço de cana (75B+25BC; 50% Bioplant® + 50% Bagaço de cana (50B+50BC; 25% Bioplant® + 75% Bagaço de cana (25B+75BC; Bagaço de cana (100%, e quatro métodos de quebra de dormência (testemunha, escarificação com o uso de lixa, imersão em água quente e escarificação com ácido sulfúrico com três repetições. Foram avaliados o índice de velocidade de emergência (IVE; o tempo médio de emergência (TME; a percentagem de germinação; a altura da parte aérea; o diâmetro do coleto; a massa seca da parte aérea; a massa seca de raiz; a massa seca total; a relação altura da parte aérea/diâmetro do coleto; a relação altura da parte aérea/massa seca da parte aérea; o índice de qualidade de Dickson; a taxa de crescimento absoluto e a taxa de crescimento relativo. Os tratamentos de imersão em água quente e de escarificação com ácido sulfúrico foram responsáveis pelos maiores percentuais de emergência e IVE, além dos de menor TME. O uso do bagaço de cana mostrou-se tecnicamente viável na composição dos substratos 75B+25BC e 50B+50BC, que, juntamente ao Bioplant®, proporcionaram as maiores taxas de crescimento e os maiores índices de qualidade das mudas de canafístula.This study aimed to evaluate the effect of different methods to break dormancy and the use of sugarcane bagasse in the composition of alternative substrates made from a mixture of commercial substrate, in canafistula (Peltophorum dubium (Sprengel Taubert seedling production The experiment was carried

  20. Chilling effect on soluble sugars, respiration rate, total phenolics, peroxidase activity and dormancy of onion bulbs Efeito do resfriamento sobre açúcares solúveis, taxa de respiração, fenóis totais, atividade de peroxidase e dormência de bulbos de cebola

    Directory of Open Access Journals (Sweden)

    Noureddine Benkeblia

    2004-06-01

    Full Text Available Besides onions being one of the most cultivated and consumed vegetables, during storage onion bulbs are still affected by many physiological, biochemical and technological factors which can influence their quality. Respiration rate (RR O2, soluble sugars (SS, total phenolics (TP, and peroxidase (POD activity were measured in inner bud tissues during a dormancy break of onion bulbs treated four weeks at 0ºC and stored in the dark at 20ºC. Control bulbs were stored simultaneously in the same condition. Breakage of dormancy was checked by the appearance of first green internal leaves by cutting longitudinally 30 bulbs. After eight weeks, RR O2 of sprouted onions was 52% higher than that of freshly harvested and dormant bulbs. One week after cooling SS decreased from 15 to 9 mg g-1 fresh weight, and then peaked from 9 to 19 mg g-1 after three weeks. For control bulbs, a similar peak was observed after six weeks. For inner buds of cold-treated onions, a slight increase of TP (from 0.17 to 0.2 mg g-1; fresh weight was observed during the first two weeks of cooling, and then a decrease to 0.11 mg g-1 was observed after eight weeks. For inner buds of control bulbs, TP also increased slightly from 0.17 to 0.2 mg g-1 after five weeks, and decreased to 0.15 mg g-1 after seven weeks when bulbs began to sprout. POD activity showed a similar pattern in relation to TP. For cold-treated bulbs, POD activity increased to 1.7 U g-1 fresh weight after two weeks, and decreased to 1.1 U g-1 during the last four weeks. For control samples, POD activity was stable during 4 weeks and decreased progressively by 29% during the last four weeks. This decrease in POD activity coincided with the decrease in TP, and coincided with onset of sprouting. With cold treatment, first sprouts were observed during the third week, while total sprouting was observed after eight weeks. In comparison, only 20% of the control bulbs sprouted after the period of 8 weeks.Além de ser uma das

  1. Superação in vitro da dormência de embriões do porta-enxerto de macieira M9 (Malus pumilla Mill. Suppression of in vitro dormancy in embryos of rootstock of apple M9 (Malus pumilla Mill.

    Directory of Open Access Journals (Sweden)

    ADRIANA CIBELE DE MESQUITA DANTAS

    2002-04-01

    Full Text Available A dormência em sementes de macieira é um dos fatores limitantes para o avanço nos programas de melhoramento genético nesta espécie. Assim, o presente estudo objetivou estudar a germinação in vitro de embriões dormentes do porta-enxerto de macieira M9, oriundos da EE São Joaquim da EPAGRI/SC. Os embriões foram excisados de sementes maduras e inoculados em meio basal MS, adicionado de sacarose (30 g.L-1, ágar (6 g.L-1, água de coco (15%, caseína hidrolisada (CH (500 mg.L-1, AIA (0 e 14 µM; AG3 (0 e 1,5 µM, Kin (5 µM, 2-iP (12 µM; BAP (4 µM. As culturas foram mantidas no escuro por 10 dias e transferidas para sala de crescimento sob regime de luz de 16 horas, temperatura de 25 ± 2°C e 40 µmol de radiação luminosa. A maior percentagem de germinação (75% foi obtida em meio MS suplementado com CH (500 mg.L-1, AIA (14 µM, AG3 (1,5 µM e Kin (5 µM. Quando a Kin foi substituída por BAP (4µM, observou-se a formação de calo, sobre o qual se originaram gemas e brotações, cujos valores médios foram de 2,3 brotos por embrião e 12,3 gemas por brotação. Em relação ao comprimento das brotações, não houve diferença significativa entre os tratamentos. A maior percentagem de indução de calos ocorreu em meio de cultura suplementado com AIA, Kin e 2-iP. O meio de cultura MS/2 suplementado com CH e água de coco e isento de fitorreguladores, resultou em 25% de germinação. Já, o número de raízes foi maior no meio de cultura MS suplementado com AIA (14 µM, AG3 (1,5 µM e CH. O comprimento médio das raízes (4,0 cm não foi afetado por nenhum tratamento em particular. Desta forma, esta técnica é uma alternativa eficiente ao uso de tratamentos de frio para a superação da dormência.The embryo dormancy in apple is a limiting factor in breeding programs with this species. Thus the present work was carried out in order to study the in vitro germination of M9 apple dormant embryos, originated from the Experimental

  2. Efeito da aplicação de cianamida hidrogenada e óleo mineral na quebra de dormência e producão do pessegueiro-'Flamecrest' Effect of the application of hidrogen cyanamid and mineral oil on dormancy breaking and peach production, cv. Flamecrest

    Directory of Open Access Journals (Sweden)

    GILMAR ARDUINO BETTIO MARODIN

    2002-08-01

    August. The Dormancy breaking, flowering, fruit set, yield, and antecipation of harvest were evaluated from plants of the folllowing treatments: 1,22; 2,45; 3,675 or 4,90 g of i.a.L-1 hydrogen cyanamid together with 10 g i.a L-1 of mineral oil or a single application of 10 g i.a L-1 mineral oil. The Control plants were not sprayed with the dormancy breaking treatment. None of the treatments resulted in sprouting antecipation of flowering buds however, plants treated with 1,22 or 4,90 g i.a L-1 hydrogen cyanamid mixed with 10 g i.a L-1 mineral oil, had a higher number of sprouted vegetative buds. There was no significant effect of the period of application on flowering and fruit set. The number of fruits thinned out from each plant was higher for the treatments with 2,45 or 4,90 g i.a L-1 of hydrogen cyanamid mixed with 10 g i.a L-1 of mineral oil. When applied to peaches trees in july, the treatments with 1,22 and 3,675 g i.a. L-1 of hydragen cyanamid and 10 g i.a. L-1 of mineral oil resulted in a higher number of fruits and total yield per plant. All the treatments, in the second apllication period, produced higher yields. The Average fruit weight, total soluble solids and pulp firmness were not influenced by the treatments.

  3. The Sprouting Potential of Dormant Buds on the Bole of Pole-Size Sugar Maple

    Science.gov (United States)

    Richard M. Godman; Gilbert A. Mattson

    1970-01-01

    A study of epicormic sprouting in pole-size sugar maples showed that all visible dormant buds on the bole were capable of producing epicormic shoots. The buds were induced to break dormancy by applying four methods of crown removal known to stimulate sprouting. The amount of crown removed determined the year that the buds broke dormancy; this may be accounted for by...

  4. Exercise-Induced Bronchoconstriction (EIB)

    Science.gov (United States)

    ... Conditions & Treatments ▸ Conditions Dictionary ▸ Exercise-Induced Bronchoconstriction Share | Exercise-Induced Bronchoconstriction (EIB) « Back to A to Z Listing Exercise-Induced Bronchoconstriction, (EIB), often known as exercise-induced ...

  5. Germination of seeds of the invasive plant Sesbania virgata (cav. pers. under effects of light, temperature, and dormancy overcoming Germinação de sementes da invasora Sesbania virgata (cav. pers. sob efeito de luz, temperatura e superação de dormência

    Directory of Open Access Journals (Sweden)

    Irenice Gomes de Oliveira

    2010-12-01

    Full Text Available The work had as objectives to evaluate the influence of the light, temperature, and chemical scarification on the germination of seeds of S. virgata, species still little studied and that is invasive in several niches of the caatinga ecosystem. The seeds of S. virgata were collected in the municipal district of Natuba-PB in March/2008. Eight treatments were used as follows: intact seeds in the presence and absence of light, at 25ºC; intact seeds in the presence and absence of light, at 30ºC; submerged seeds in sulfuric acid for five minutes in the presence and absence of light, at 25ºC; submerged seeds in sulfuric acid for five minutes in the presence and absence of light, at 30ºC. The germination tests were accomplished in germination cameras under light and continuous darkness at constant temperatures of 25ºC and 30ºC, in a 12 hours photoperiod. The seeds were put to germinate in plastic boxes (gerbox with filter paper. The seeds of S. virgata have tegument dormancy and show low germination tax when intact, which is a strategy for seed banks formation. The acid scarification increased germination percentage and speed germination index. Este trabalho teve como objetivos avaliar a influência da luz, da temperatura e da escarificação química sobre a germinação de sementes de S. virgata, espécie ainda pouco estudada e que se constata invasora em diversos nichos do bioma Caatinga. Sementes de S. virgata foram coletadas no município de Natuba-PB em março de 2008 e submetidas a oito tratamentos, descritos a seguir: sementes intactas, na presença e ausência de luz, a 25ºC; sementes intactas na presença e ausência de luz, a 30ºC; sementes imersas em ácido sulfúrico por cinco minutos na presença e ausência de luz, a 25ºC; sementes imersas em ácido sulfúrico por cinco minutos na presença e ausência de luz, a 30ºC. Para estimar os efeitos dos tratamentos foram realizados testes de germinação em câmaras de germinação sob

  6. Fatores que afetam a germinação e a emergência de Xanthium strumarim L.: dormência, qualidade da luz e profundidade de semeadura Factors affecting germination and emergence of Xanthium strumarium L.: dormancy, light quality and sowing depth

    Directory of Open Access Journals (Sweden)

    Roberto E.B. Toledo

    1993-01-01

    Full Text Available Foram conduzidos três ensaios com o objetivo de estudar os efeitos de diferentes métodos de quebra de dormência das sementes, da qualidade da luz e da profundidade de semeadura na germinação e emergência do Xanthium strumarim L. (carrapichão. No primeiro ensaio, sob condições de câmara de crescimento, os tratamentos constaram de 5 métodos de quebra de dormência: mecânico (lixa, químico (H2SO4 conc. por 10 min., pré-tratamento em água (imersão por 2 horas, físico (choque térmico: água à 80oC por 2 min. e testemunha, que proporcionaram 100%, 93%, 93%, 87% e 80% de germinação, respectivamente, sem haver diferença estatística entre os mesmos. O pré-tratamento em água apresentou menor índice de velocidade de germinação (IVG e os demais não diferiram significativamente entre si. No segundo ensaio, também sob condições de câmara de crescimento, os tratamentos de qualidade da luz constaram de 6 filtros de luz, que resultaram nas seguintes porcentagens de germinação: azul - com refletividade máxima a 450 nm (13%, verde-500 nm (33%, vermelho-700 nm (13%, vermelho/distante-760 nm (7%, ausência de luz (26% e transparente - sem absortividade na região de 380 a 760 nm (testemunha, 73%, indicando sensibilidade das sementes à qualidade de luz. No terceiro ensaio, sob condições de casa-de-vegetação, os tratamentos foram diferentes profundidades de semeadura (0 a 20 cm, em intervalos de 2 cm, sendo que o máximo de emergência ocorreu no intervalo de 0 a 8 cm, no qual foi observado 67% de emergência do carrapichão, com maior índice de velocidade emergência (IVE, sendo que após os 16 cm, praticamente não houve emergência.Three trials were carried out to study the effects of different methods to overcome dormancy, light quality and sowing depth on the germination and emergence of Xanthium strumarim L. (cocklebur. In the first trial, under growth chamber conditions, the treatments consisted of 5 methods of seed

  7. DETERMINATION OF INHIBITORS, DORMANCY BREAKING AND SEED HEALTH IN CUTIEIRA

    Directory of Open Access Journals (Sweden)

    José Maria Gomes Neves2

    2013-12-01

    was completely randomized, factorial 2 x 5, with two types of seed from freshly harvested fruits and remnants and five pre-germination treatments. The seed coat removal promotes increased germination and seed vigor derived from harvested fruits. Fungi identified in the cutieira seeds were Aspergillus niger, Aspergillus flavus, Penicillium sp. and Rhizopus sp.

  8. Characterization of reproductive dormancy in male Drosophila melanogaster

    Czech Academy of Sciences Publication Activity Database

    Kubrak, O. I.; Kučerová, Lucie; Theopold, U.; Nylin, S.; Nässel, D. R.

    2016-01-01

    Roč. 7, NOV 24 (2016), č. článku 572. ISSN 1664-042X Institutional support: RVO:60077344 Keywords : Drosophila melanogaster * diapause * reproduction Subject RIV: ED - Physiology Impact factor: 4.134, year: 2016 http://journal.frontiersin.org/article/10.3389/fphys.2016.00572/full

  9. Microenvironments and Signaling Pathways Regulating Early Dissemination, Dormancy, and Metastasis

    Science.gov (United States)

    2015-09-01

    that occupies the lower right quadrant of the video . Still images of movie are shown in Figure 6A. Movie S3: Two-photon imaging of MMTV-HER2-CFP mice...was used to permeabilize cells and blocking was done using .1% BSA in PBS with 10% Normal Goat Serum or Normal Donkey Serum (Sigma D9663). Primary...Alexaflour 568 goat-anti rabbit, Alexaflour 488 donkey -anti goat, Alexaflour 547 donkey anti rabbit. Slides were mounted using Prolong Antifade

  10. 14 CFR 204.7 - Revocation for dormancy.

    Science.gov (United States)

    2010-01-01

    .... Such filings shall be addressed to the Documentary Services Division, Department of Transportation... carrier by the FAA. (Approved by the Office of Management and Budget under control number 2106-0023) ...

  11. Spiritual Dormancy: The Strategic Effect of the Depravation of God

    Science.gov (United States)

    2013-03-01

    is genetically "hardwired" into the human condition. One controversial hypothesis, 4 the ‘God gene hypothesis,’ states that some variants of a...God in the profession of arms and the body politic. 22 Endnotes 1 Stewart W. Husted, George C. Marshall: The Rubrics of Leadership, (Carlisle

  12. Breaking of Judas tree seed dormancy by plant hormone treatments

    Directory of Open Access Journals (Sweden)

    Grbić Mihailo

    2014-01-01

    Full Text Available The study deals with the influence of growth regulators on the germination of Judas tree (Cercis siliquastrum L. seed which is double dormant. We simultaneously tested seeds prepared in the conventional procedure: scarification + stratification and scarified seeds treated with phytohormones from the groups of gibberellins, auxin and cytokinins. The results indicate a positive effect of gibberellic acid (GA, as well as some combinations of this phytohormone with others. Recommendations for practice are to combine the conventional procedure with GA. The procedure may shorten the duration of stratification; the application of GA should follow stratification because the temperature of 4°C does not provide growth regulators activity. The study results can serve as the base for easier generative reproduction of this valuable woody ornamental species which could have a wide use in changed climate conditions. [Projekat Ministarstva nauke Republike Srbije, br. 43007: Studying climate change and its influence on the environment: impacts, adaptation and mitigation

  13. Macrophage Functions in Early Dissemination and Dormancy of Breast Cancer

    Science.gov (United States)

    2016-09-01

    mammary gland development 17,18, 69   arguing that normal mammary epithelial cells cooperate with these innate immune cells 70   for invasive... cells lacking 218     11   lymphoid and granulocytic markers (Supplementary Fig.3B). viSNE plots 30 of myelo-219   monocytic cells (Fig.5A...macrophages are actively recruited by pre-malignant ErbB2 overexpressing cancer cells and that these intra-epithelial macrophages then produce factors

  14. Microenvironments and Signaling Pathways Regulating Early Dissemination, Dormancy, and Metastasis

    Science.gov (United States)

    2016-09-01

    regulators of branching morphogenesis during mammary gland development 17,18, arguing that normal mammary epithelial cells cooperate with these innate ...CD45+CD11b+F4/80+ cells lacking lymphoid and granulocytic markers (Supplementary Fig.3B). viSNE plots 30 of myelo- monocytic cells (Fig.5A) showed that...cancer cells and how the microenvironment in these primary sites named P-TMEM (Primary Tumor Microenvironment of Metastases) contribute to early

  15. Dormancy activation mechanism of oral cavity cancer stem cells.

    Science.gov (United States)

    Chen, Xiang; Li, Xin; Zhao, Baohong; Shang, Dehao; Zhong, Ming; Deng, Chunfu; Jia, Xinshan

    2015-07-01

    Radiotherapy and chemotherapy are targeted primarily at rapidly proliferating cancer cells and are unable to eliminate cancer stem cells in the G0 phase. Thus, these treatments cannot prevent the recurrence and metastasis of cancer. Understanding the mechanisms by which cancer stem cells are maintained in the dormant G0 phase, and how they become active is key to developing new cancer therapies. The current study found that the anti-cancer drug 5-fluorouracil, acting on the oral squamous cell carcinoma KB cell line, selectively killed proliferating cells while sparing cells in the G0 phase. Bisulfite sequencing PCR showed that demethylation of the Sox2 promoter led to the expression of Sox2. This then resulted in the transformation of cancer stem cells from the G0 phase to the division stage and suggested that the transformation of cancer stem cells from the G0 phase to the division stage is closely related to an epigenetic modification of the cell.

  16. Insights into horizontal acquisition patterns of dormancy and ...

    Indian Academy of Sciences (India)

    2016-07-22

    Jul 22, 2016 ... ed the horizontal acquisition of fatty acid synthesis genes from α-proteobacteria .... of the genes related to fatty acid, polyketide or lipoprotein metabolism in M. ..... Basic local alignment search tool. J. Mol. Biol. 215 403–410.

  17. Physiological analysis of methods to relieve dormancy of lettuce seeds

    NARCIS (Netherlands)

    Weges, R.

    1987-01-01

    Low maximum temperature of germination restricts the cultivation of a number of lettuce cultivars to temperate conditions. Pretreatments have been studied that increase the maximum germination temperature, which is characterized by the temperature for 50% germination (T

  18. Insights into horizontal acquisition patterns of dormancy and ...

    Indian Academy of Sciences (India)

    Horizontal Gene Transfer (HGT) events, initially thought to be rare in Mycobacterium tuberculosis, have recentlybeen shown to be involved in the acquisition of virulence operons in M. tuberculosis. We have developed a newpartitioning framework based HGT prediction algorithm, called Grid3M, and applied the same for the ...

  19. Understanding Tumor Dormancy as a Means of Secondary Prevention

    Science.gov (United States)

    2017-10-01

    within the micro - environment that contact cancer cells. This molecular description of the dormant state will allow us to perform loss-of-function and...understand further the biology of retinal ganglion loss. Role: Primary Investigator OVERLAP None Cancer Research UK Cambridge Institute ACTIVE...the biological functions and mechanisms of non-coding RNAs; to attempt to tackle critical problems in cancer biology , with a major focus on breast and

  20. Understanding Tumor Dormancy as a Means of Secondary Prevention

    Science.gov (United States)

    2015-10-14

    Hughes Medical Institute • National Philanthropic Trust • PEW Charitable Trust • 5 R01 HG005238-04 Greg Hannon has been replaced as the Primary...OVERLAP: None NBCC (Hannon) 10/10/13 – 10/09/15 0.00 calendar* National Philanthropic Trust Research and analysis activities in support of...Investigator/Senior Personnel NBCC (Hannon) 10/10/13 – 10/09/14 0.00 calendar* National Philanthropic Trust Research and analysis activities in

  1. Ga 3 -Mediated Dormancy Alleviation In The Reputed African Potato ...

    African Journals Online (AJOL)

    In the ex vitro experiment, intact seeds were sown and left to germinate in a potting soil mix under greenhouse conditions. Results: Highest levels of germination (36.7-60.0% in the light and 36.7-46.7% in the dark) were achieved by treating mechanically scarified seeds with GA3 at various concentrations for 24 h. This was ...

  2. Macrophage Function in Early Dissemination and Dormancy of Breast Cancer

    Science.gov (United States)

    2015-09-01

    Obstetrics and Gynecology, University Hospital Frankfurt am Main, Germany, 4Department of Obstetrics and Gynecology, Heinrich Heine University, Duesseldorf...insight into the understanding of the natural history of metastatic disease by discovering that MTMs propel early dissemination and that combined

  3. Environmental regulation of dormancy loss in seeds of Lomatium dissectum

    Science.gov (United States)

    Melissa Dawn Scholten

    2011-01-01

    Lomatium dissectum (Nutt.) Mathias & Constance is a perennial plant found across much of western North America. For disturbed lands within this range, there is interest in using L. dissectum in restoration. A problem in the propagation of L. dissectum is that at the time of dispersal the seeds are dormant. Thus, prior to usage in restoration projects the type of...

  4. Induced pluripotency with endogenous and inducible genes

    International Nuclear Information System (INIS)

    Duinsbergen, Dirk; Eriksson, Malin; Hoen, Peter A.C. 't; Frisen, Jonas; Mikkers, Harald

    2008-01-01

    The recent discovery that two partly overlapping sets of four genes induce nuclear reprogramming of mouse and even human cells has opened up new possibilities for cell replacement therapies. Although the combination of genes that induce pluripotency differs to some extent, Oct4 and Sox2 appear to be a prerequisite. The introduction of four genes, several of which been linked with cancer, using retroviral approaches is however unlikely to be suitable for future clinical applications. Towards developing a safer reprogramming protocol, we investigated whether cell types that express one of the most critical reprogramming genes endogenously are predisposed to reprogramming. We show here that three of the original four pluripotency transcription factors (Oct4, Klf4 and c-Myc or MYCER TAM ) induced reprogramming of mouse neural stem (NS) cells exploiting endogenous SoxB1 protein levels in these cells. The reprogrammed neural stem cells differentiated into cells of each germ layer in vitro and in vivo, and contributed to mouse development in vivo. Thus a combinatorial approach taking advantage of endogenously expressed genes and inducible transgenes may contribute to the development of improved reprogramming protocols

  5. Diet induced thermogenesis

    Directory of Open Access Journals (Sweden)

    Westerterp KR

    2004-08-01

    Full Text Available Objective Daily energy expenditure consists of three components: basal metabolic rate, diet-induced thermogenesis and the energy cost of physical activity. Here, data on diet-induced thermogenesis are reviewed in relation to measuring conditions and characteristics of the diet. Methods Measuring conditions include nutritional status of the subject, physical activity and duration of the observation. Diet characteristics are energy content and macronutrient composition. Results Most studies measure diet-induced thermogenesis as the increase in energy expenditure above basal metabolic rate. Generally, the hierarchy in macronutrient oxidation in the postprandial state is reflected similarly in diet-induced thermogenesis, with the sequence alcohol, protein, carbohydrate, and fat. A mixed diet consumed at energy balance results in a diet induced energy expenditure of 5 to 15 % of daily energy expenditure. Values are higher at a relatively high protein and alcohol consumption and lower at a high fat consumption. Protein induced thermogenesis has an important effect on satiety. In conclusion, the main determinants of diet-induced thermogenesis are the energy content and the protein- and alcohol fraction of the diet. Protein plays a key role in body weight regulation through satiety related to diet-induced thermogenesis.

  6. Induced quantum conformal gravity

    International Nuclear Information System (INIS)

    Novozhilov, Y.V.; Vassilevich, D.V.

    1988-11-01

    Quantum gravity is considered as induced by matter degrees of freedom and related to the symmetry breakdown in the low energy region of a non-Abelian gauge theory of fundamental fields. An effective action for quantum conformal gravity is derived where both the gravitational constant and conformal kinetic term are positive. Relation with induced classical gravity is established. (author). 15 refs

  7. Induced radioactivity at CERN

    CERN Multimedia

    1970-01-01

    A description of some of the problems and some of the advantages associated with the phenomenon of induced radioactivity at accelerator centres such as CERN. The author has worked in this field for several years and has recently written a book 'Induced Radioactivity' published by North-Holland.

  8. Diet induced thermogenesis

    NARCIS (Netherlands)

    Westerterp, K.R.

    2004-01-01

    OBJECTIVE: Daily energy expenditure consists of three components: basal metabolic rate, diet-induced thermogenesis and the energy cost of physical activity. Here, data on diet-induced thermogenesis are reviewed in relation to measuring conditions and characteristics of the diet. METHODS: Measuring

  9. Bleomycin-induced pneumonitis

    NARCIS (Netherlands)

    S. Sleijfer (Stefan)

    2001-01-01

    textabstractThe cytotoxic agent bleomycin is feared for its induction of sometimes fatal pulmonary toxicity, also known as bleomycin-induced pneumonitis (BIP). The central event in the development of BIP is endothelial damage of the lung vasculature due to bleomycin-induced

  10. Induced abortion in Taiwan.

    Science.gov (United States)

    Wang, P D; Lin, R S

    1995-04-01

    Induced abortion is widely practised in Taiwan; however, it had been illegal until 1985. It was of interest to investigate induced abortion practices in Taiwan after its legalization in 1985 in order to calculate the prevalence rate and ratio of induced abortion to live births and to pregnancies in Taiwan. A study using questionnaires through personal interviews was conducted on more than seventeen thousand women who attended a family planning service in Taipei metropolitan areas between 1991 and 1992. The reproductive history and sexual behaviour of the subjects were especially focused on during the interviews. Preliminary findings showed that 46% of the women had a history of having had an induced abortion. Among them, 54.8% had had one abortion, 29.7% had had two, and 15.5% had had three or more. The abortion ratio was 379 induced abortions per 1,000 live births and 255 per 1,000 pregnancies. The abortion ratio was highest for women younger than 20 years of age, for aboriginal women and for nulliparous women. When logistic regression was used to control for confounding variables, we found that the number of previous live births is the strongest predictor relating to women seeking induced abortion. In addition, a significant positive association exists between increasing number of induced abortions and cervical dysplasia.

  11. Transcriptome and Metabolite Changes during Hydrogen Cyanamide-Induced Floral Bud Break in Sweet Cherry

    OpenAIRE

    Ionescu, Irina A.; L?pez-Ortega, Gregorio; Burow, Meike; Bayo-Canha, Almudena; Junge, Alexander; Gericke, Oliver; M?ller, Birger L.; S?nchez-P?rez, Raquel

    2017-01-01

    Release of bud dormancy in perennial woody plants is a temperature-dependent process and thus flowering in these species is heavily affected by climate change. The lack of cold winters in temperate growing regions often results in reduced flowering and low fruit yields. This is likely to decrease the availability of fruits and nuts of the Prunus spp. in the near future. In order to maintain high yields, it is crucial to gain detailed knowledge on the molecular mechanisms controlling the relea...

  12. Photon induced reactions

    International Nuclear Information System (INIS)

    Mecking, B.A.

    1982-04-01

    Various aspects of medium energy nuclear reactions induced by real photons are reviewed. Special emphasis is put on high accuracy experiments that will become possible with the next generation of electron accelerators. (orig.)

  13. Induced Noise Control

    National Research Council Canada - National Science Library

    Maidanik, G

    2002-01-01

    The induced noise control parameter is defined in terms of the ratio of the stored energy in a master dynamic system, when it is coupled to an adjunct dynamic system, to that stored energy when the coupling is absent...

  14. Beam induced RF heating

    CERN Document Server

    Salvant, B; Arduini, G; Assmann, R; Baglin, V; Barnes, M J; Bartmann, W; Baudrenghien, P; Berrig, O; Bracco, C; Bravin, E; Bregliozzi, G; Bruce, R; Bertarelli, A; Carra, F; Cattenoz, G; Caspers, F; Claudet, S; Day, H; Garlasche, M; Gentini, L; Goddard, B; Grudiev, A; Henrist, B; Jones, R; Kononenko, O; Lanza, G; Lari, L; Mastoridis, T; Mertens, V; Métral, E; Mounet, N; Muller, J E; Nosych, A A; Nougaret, J L; Persichelli, S; Piguiet, A M; Redaelli, S; Roncarolo, F; Rumolo, G; Salvachua, B; Sapinski, M; Schmidt, R; Shaposhnikova, E; Tavian, L; Timmins, M; Uythoven, J; Vidal, A; Wenninger, J; Wollmann, D; Zerlauth, M

    2012-01-01

    After the 2011 run, actions were put in place during the 2011/2012 winter stop to limit beam induced radio frequency (RF) heating of LHC components. However, some components could not be changed during this short stop and continued to represent a limitation throughout 2012. In addition, the stored beam intensity increased in 2012 and the temperature of certain components became critical. In this contribution, the beam induced heating limitations for 2012 and the expected beam induced heating limitations for the restart after the Long Shutdown 1 (LS1) will be compiled. The expected consequences of running with 25 ns or 50 ns bunch spacing will be detailed, as well as the consequences of running with shorter bunch length. Finally, actions on hardware or beam parameters to monitor and mitigate the impact of beam induced heating to LHC operation after LS1 will be discussed.

  15. Vitiligo, drug induced (image)

    Science.gov (United States)

    ... this person's face have resulted from drug-induced vitiligo. Loss of melanin, the primary skin pigment, occasionally ... is the case with this individual. The typical vitiligo lesion is flat and depigmented, but maintains the ...

  16. Seizure induces activation of multiple subtypes of neural progenitors and growth factors in hippocampus with neuronal maturation confined to dentate gyrus

    Energy Technology Data Exchange (ETDEWEB)

    Indulekha, Chandrasekharan L.; Sanalkumar, Rajendran [Neuro Stem Cell Biology Laboratory, Department of Neurobiology, Rajiv Gandhi Center for Biotechnology, Thiruvananthapuram, Kerala 695 014 (India); Thekkuveettil, Anoopkumar [Molecular Medicine, Biomedical Technology Wing, Sree Chitra Thirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala (India); James, Jackson, E-mail: jjames@rgcb.res.in [Neuro Stem Cell Biology Laboratory, Department of Neurobiology, Rajiv Gandhi Center for Biotechnology, Thiruvananthapuram, Kerala 695 014 (India)

    2010-03-19

    Adult hippocampal neurogenesis is altered in response to different physiological and pathological stimuli. GFAP{sup +ve}/nestin{sup +ve} radial glial like Type-1 progenitors are considered to be the resident stem cell population in adult hippocampus. During neurogenesis these Type-1 progenitors matures to GFAP{sup -ve}/nestin{sup +ve} Type-2 progenitors and then to Type-3 neuroblasts and finally differentiates into granule cell neurons. In our study, using pilocarpine-induced seizure model, we showed that seizure initiated activation of multiple progenitors in the entire hippocampal area such as DG, CA1 and CA3. Seizure induction resulted in activation of two subtypes of Type-1 progenitors, Type-1a (GFAP{sup +ve}/nestin{sup +ve}/BrdU{sup +ve}) and Type-1b (GFAP{sup +ve}/nestin{sup +ve}/BrdU{sup -ve}). We showed that majority of Type-1b progenitors were undergoing only a transition from a state of dormancy to activated form immediately after seizures rather than proliferating, whereas Type-1a showed maximum proliferation by 3 days post-seizure induction. Type-2 (GFAP{sup -ve}/nestin{sup +ve}/BrdU{sup +ve}) progenitors were few compared to Type-1. Type-3 (DCX{sup +ve}) progenitors showed increased expression of immature neurons only in DG region by 3 days after seizure induction indicating maturation of progenitors happens only in microenvironment of DG even though progenitors are activated in CA1 and CA3 regions of hippocampus. Also parallel increase in growth factors expression after seizure induction suggests that microenvironmental niche has a profound effect on stimulation of adult neural progenitors.

  17. Terahertz Induced Electromigration

    DEFF Research Database (Denmark)

    Strikwerda, Andrew; Zalkovskij, Maksim; Iwaszczuk, Krzysztof

    2014-01-01

    We report the first observation of THz-field-induced electromigration in subwavelength metallic gap structures after exposure to intense single-cycle, sub-picosecond electric field transients of amplitude up to 400 kV/cm.......We report the first observation of THz-field-induced electromigration in subwavelength metallic gap structures after exposure to intense single-cycle, sub-picosecond electric field transients of amplitude up to 400 kV/cm....

  18. Diet induced thermogenesis

    OpenAIRE

    Westerterp KR

    2004-01-01

    Objective Daily energy expenditure consists of three components: basal metabolic rate, diet-induced thermogenesis and the energy cost of physical activity. Here, data on diet-induced thermogenesis are reviewed in relation to measuring conditions and characteristics of the diet. Methods Measuring conditions include nutritional status of the subject, physical activity and duration of the observation. Diet characteristics are energy content and macronutrient composition. Resu...

  19. Laser-induced interactions

    International Nuclear Information System (INIS)

    Green, W.R.

    1979-01-01

    This dissertation discusses some of the new ways that lasers can be used to control the energy flow in a medium. Experimental and theoretical considerations of the laser-induced collision are discussed. The laser-induced collision is a process in which a laser is used to selectively transfer energy from a state in one atomic or molecular species to another state in a different species. The first experimental demonstration of this process is described, along with later experiments in which lasers were used to create collisional cross sections as large as 10 - 13 cm 2 . Laser-induced collisions utilizing both a dipole-dipole interaction and dipole-quadrupole interaction have been experimentally demonstrated. The theoretical aspects of other related processes such as laser-induced spin-exchange, collision induced Raman emission, and laser-induced charge transfer are discussed. Experimental systems that could be used to demonstrate these various processes are presented. An experiment which produced an inversion of the resonance line of an ion by optical pumping of the neutral atom is described. This type of scheme has been proposed as a possible method for constructing VUV and x-ray lasers

  20. Radiation-induced apoptosis

    International Nuclear Information System (INIS)

    Ohyama, Harumi

    1995-01-01

    Apoptosis is an active process of gene-directed cellular self-destruction that can be induced in many cell types via numerous physiological and pathological stimuli. We found that interphasedeath of thymocytes is a typical apoptosis showing the characteristic features of apoptosis including cell shrinkage, chromatin condensation and DNA degradation. Moderate dose of radiation induces extensive apoptosis in rapidly proliferating cell population such as the epithelium of intestinal crypt. Recent reports indicate that the ultimate form of radiation-induced mitotic death in several cells is also apoptosis. One of the hallmarks of apoptosis is the enzymatic internucleosomal degradation of chromatin DNA. We identified an endonuclease responsible for the radiation-induced DNA degradation in rat thymocytes. The death-sparing effects of interrupting RNA and protein synthesis suggested a cell genetic program for apoptosis. Apoptosis of thymocytes initiated by DNA damage, such as radiation and radio mimetic substance, absolutely requires the protein of p53 cancer suppresser gene. The cell death induced by glucocorticoid, or aging, has no such requirement. Expression of oncogene bcl-2 rescues cells from the apoptosis. Massive apoptosis in radiosensitive cells induced by higher dose radiation may be fatal. It is suggested that selective apoptotic elimination of cells would play an important role for protection against carcinogenesis and malformation through removal of cells with unrepaired radiation-induced DNA damages. Data to evaluate the significance of apoptosis in the radiation risk are still poor. Further research should be done in order to clarify the roles of the cell death on the acute and late effects of irradiation. (author)

  1. Chemical-induced Vitiligo

    Science.gov (United States)

    Harris, John E.

    2016-01-01

    Synopsis Chemical-induced depigmentation of the skin has been recognized for over 75 years, first as an occupational hazard but then extending to those using household commercial products as common as hair dyes. Since their discovery, these chemicals have been used therapeutically in patients with severe vitiligo to depigment their remaining skin and improve their appearance. The importance of recognizing this phenomenon was highlighted during an outbreak of vitiligo in Japan during the summer of 2013, when over 16,000 users of a new skin lightening cosmetic cream developed skin depigmentation at the site of contact with the cream and many in remote areas as well. Depigmenting chemicals appear to be analogs of the amino acid tyrosine that disrupt melanogenesis and result in autoimmunity and melanocyte destruction. Because chemical-induced depigmentation is clinically and histologically indistinguishable from non-chemically induced vitiligo, and because these chemicals appear to induce melanocyte autoimmunity, this phenomenon should be known as “chemical-induced vitiligo”, rather than less accurate terms that have been previously used. PMID:28317525

  2. [Drug induced diarrhea].

    Science.gov (United States)

    Morard, Isabelle; Hadengue, Antoine

    2008-09-03

    Diarrhea is a frequent adverse event involving the most frequently antibiotics, laxatives and NSAI. Drug induced diarrhea may be acute or chronic. It may be due to expected, dose dependant properties of the drug, to immuno-allergic or bio-genomic mechanisms. Several pathophysiological mechanisms have been described resulting in osmotic, secretory or inflammatory diarrhea, shortened transit time, or malabsorption. Histopathological lesions sometimes associated with drug induced diarrhea are usually non specific and include ulcerations, inflammatory or ischemic lesions, fibrous diaphragms, microscopic colitis and apoptosis. The diagnosis of drug induced diarrhea, sometimes difficult to assess, relies on the absence of other obvious causes and on the rapid disappearance of the symptoms after withdrawal of the suspected drug.

  3. Peripheral kisspeptin reverses short photoperiod-induced gonadal regression in Syrian hamsters by promoting GNRH release

    DEFF Research Database (Denmark)

    Ansel, L; Bentsen, A H; Ancel, C

    2011-01-01

    In seasonal breeders, reproduction is synchronised by day length via the pineal hormone melatonin. In short winter days (short day, SD), the Syrian hamster displays a complete gonadal atrophy together with a marked reduction in expression of kisspeptins (Kp), a family of potent hypothalamic stimu...

  4. Rosuvastatin-induced pemphigoid.

    LENUS (Irish Health Repository)

    Murad, Aizuri A

    2012-01-01

    Statins are widely prescribed medications and very well tolerated. Rosuvastatin is another member of this drug used to treat dyslipidaemia. It is a competitive inhibitor of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase. Immunobullous disease is usually idiopathic but can be drug-induced. Both idiopathic and iatrogenic forms share common clinical and immunohistological features. The authors report a case of pemphigoid induced by rosuvastatin, a commonly prescribed medication. To our knowledge, there is limited report on rosuvastatin associated with pemphigoid in the literature.

  5. Cervical osteophyte induced dysphagia

    International Nuclear Information System (INIS)

    Davies, R.P.; Sage, M.R.; Brophy, B.P.

    1989-01-01

    Although cervical spondylosis is a common disorder, dysphagia induced by osteophyte formation is uncommon. Fewer than one hundred cases of cervical osteophyte induced dysphagia have been reported, with little attention to the diagnosis by barium swallow. The radiological features of two cases treated surgically with good results are described. Both cases complained of dysphagia while one had associated respiratory obstruction on forward flexion of his neck. The features on barium study of cervical osteophytes causing dysphagia include deformity at the level of osteophyte formation, in both AP and lateral projections. Tracheal aspirations due to deformity at the laryngeal inlet and interference with epiglottic retroversion may be present. 8 refs., 3 figs

  6. Exercise-induced rhabdomyolysis.

    Science.gov (United States)

    Lee, George

    2014-11-03

    Exercise-induced rhabdomyolysis, or exertional rhabdomyolysis (ER), is a clinical entity typically considered when someone presents with muscle stiffness, swelling, and pain out of proportion to the expected fatigue post exercise. The diagnosis is confirmed by myoglobinuria, and an elevated serum Creatinine Phosphokinase (CPK) level, usually 10 times the normal range. However, an elevation in CPK is seen in most forms of strenuous exercise, up to 20 times the upper normal range. Therefore, there is no definitive pathologic CPK cut-off. Fortunately the dreaded complication of acute renal failure is rare compared to other forms rhabdomyolysis. We review the risks, diagnosis, clinical course and treatment for exercise- induced rhabdomyolysis.

  7. Migraine induced by hypoxia

    DEFF Research Database (Denmark)

    Arngrim, Nanna; Schytz, Henrik Winther; Britze, Josefine

    2016-01-01

    in the visual cortex were measured by proton magnetic resonance spectroscopy. The circumference of cranial arteries was measured by 3 T high-resolution magnetic resonance angiography. Hypoxia induced migraine-like attacks in eight patients compared to one patient after sham (P = 0.039), aura in three...... and possible aura in 4 of 15 patients. Hypoxia did not change glutamate concentration in the visual cortex compared to sham, but increased lactate concentration (P = 0.028) and circumference of the cranial arteries (P ... suggests that hypoxia may provoke migraine headache and aura symptoms in some patients. The mechanisms behind the migraine-inducing effect of hypoxia should be further investigated....

  8. Airbag induced corneal ectasia.

    Science.gov (United States)

    Mearza, Ali A; Koufaki, Fedra N; Aslanides, Ioannis M

    2008-02-01

    To report a case of airbag induced corneal ectasia. Case report. A patient 3 years post-LASIK developed bilateral corneal ectasia worse in the right eye following airbag deployment in a road traffic accident. At last follow up, best corrected vision was 20/40 with -4.00/-4.00 x 25 in the right eye and 20/25 with -1.25/-0.50 x 135 in the left eye. This is a rare presentation of trauma induced ectasia in a patient post-LASIK. It is possible that reduction in biomechanical integrity of the cornea from prior refractive surgery contributed to this presentation.

  9. Sleep-inducing factors.

    Science.gov (United States)

    García-García, Fabio; Acosta-Peña, Eva; Venebra-Muñoz, Arturo; Murillo-Rodríguez, Eric

    2009-08-01

    Kuniomi Ishimori and Henri Piéron were the first researchers to introduce the concept and experimental evidence for a chemical factor that would presumably accumulate in the brain during waking and eventually induce sleep. This substance was named hypnotoxin. Currently, the variety of substances which have been shown to alter sleep includes peptides, cytokines, neurotransmitters and some substances of lipidic nature, many of which are well known for their involvement in other biological activities. In this chapter, we describe the sleep-inducing properties of the vasoactive intestinal peptide, prolactin, adenosine and anandamide.

  10. Foliar glyphosate treatment alters transcript and hormone profiles in crown buds of leafy spurge and induces dwarfed and bushy phenotypes throughout its perennial life cycle

    Science.gov (United States)

    Leafy spurge (Euphorbia esula) is an invasive weed of North America and its perennial nature is attributed to underground adventitious buds (UABs) that undergo seasonal cycles of para-, endo- and eco-dormancy. Recommended field rates of glyphosate (~1 kg/ha) destroys above-ground shoots of leafy spu...

  11. Inducible laryngeal obstruction

    DEFF Research Database (Denmark)

    Halvorsen, Thomas; Walsted, Emil Schwarz; Bucca, Caterina

    2017-01-01

    Inducible laryngeal obstruction (ILO) describes an inappropriate, transient, reversible narrowing of the larynx in response to external triggers. ILO is an important cause of a variety of respiratory symptoms and can mimic asthma. Current understanding of ILO has been hampered by imprecise nomenc...

  12. Drug-induced apnea.

    Science.gov (United States)

    Boutroy, M J

    1994-01-01

    Drugs have been in the past and will in the future still be liable to induce apnea in neonates, infants and older children. At these different stages of development, the child may be abnormally vulnerable to respiratory disorders and apnea, and doses of drugs, without any abnormal side effects in adult patients, can be harmful in younger subjects. Drugs responsible for apnea during development are numerous, but more than half of the problems are induced by sedatives and hypnotics, among which phenothiazines, barbiturates, benzodiazepines (included transplacentally acquired) and general anesthetics are a few. Other pharmacological families are apnea inducers in the neonatal period and childhood: analgesics and opioid narcotics, agents acting at the levels of neuromuscular function and autonomic ganglia, and cardiovascular agents. The pathogenesis of these apneas depends on the disturbance of any mechanism responsible for the respiratory activity: medullary centers and brain stem structures, afferent influx to CNS, sleep stages, upper airways, lungs and respiratory muscles. At key stages such as birth and infancy, drugs may emphasize the particular sensitivity of the mechanisms responsible for inducing apnea. This might explain unexpected respiratory disorders during development.

  13. Metronidazole-Induced Pancreatitis

    Directory of Open Access Journals (Sweden)

    E. O'Halloran

    2010-01-01

    Conclusion. This case provides the eighth report of Metronidazole induced pancreatitis. All of the cases were reported in females and ran a benign course.Early diagnosis, discontinuation of the drug and supportive care will lead to a successful recovery in the majority of cases.

  14. XTC-induced hepatitis

    NARCIS (Netherlands)

    Oranje, W.A.; van Pol, V.; van der Wurff, A.A.; Zeijen, R.N.; Stockbrügger, R.W.; Arends, J.W.

    1994-01-01

    XTC-induced hepatitis. Oranje WA, von Pol P, vd Wurff A, Zeijen RN, Stockbrugger RW, Arends JW. Department of Internal Medicine, University Hospital, Maastricht, Netherlands. An increasing number of severe complications associated with the use of XTC is being reported. After 11 earlier case reports

  15. Bowthruster-induced damage

    NARCIS (Netherlands)

    Schokking, L.A.; Janssen, P.C.; Verhagen, H.J.

    2003-01-01

    The stability of stones in propeller-induced jet wash is still difficult to predict. Especially the trend of bowthrusters increasing in size and power in sea going ships (especially ferries) over the last years may be a reason for concern when dealing with the protection of slopes and beds. But also

  16. Muon-induced fission

    International Nuclear Information System (INIS)

    Polikanov, S.

    1980-01-01

    A review of recent experimental results on negative-muon-induced fission, both of 238 U and 232 Th, is given. Some conclusions drawn by the author are concerned with muonic atoms of fission fragments and muonic atoms of the shape isomer of 238 U. (author)

  17. Calotropis procera -induced keratitis

    Directory of Open Access Journals (Sweden)

    Pandey Nidhi

    2009-01-01

    Full Text Available Calotropis procera produces copious amounts of latex, which has been shown to possess several pharmacological properities. Its local application produces intense inflammatory response. In the 10 cases of Calotropis procera -induced keratitis reported here, the clinical picture showed corneal edema with striate keratopathy without any evidence of intraocular inflammation. The inflammation was reversed by the local application of steroid drops.

  18. Induced nuclear beta decay

    International Nuclear Information System (INIS)

    Reiss, H.R.

    1986-01-01

    Certain nuclear beta decay transitions normally inhibited by angular momentum or parity considerations can be induced to occur by the application of an electromagnetic field. Such decays can be useful in the controlled production of power, and in fission waste disposal

  19. Hyperthermia-induced apoptosis

    NARCIS (Netherlands)

    Nijhuis, E.H.A.

    2008-01-01

    This thesis describes a number of studies that investigated several aspects of heat-induced apoptosis in human lymphoid malignancies. Cells harbour both pro- and anti-apoptotic proteins and the balance between these proteins determines whether a cell is susceptible to undergo apoptosis. In this

  20. Drug induced aseptic meningitis

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2013-09-29

    Sep 29, 2013 ... Abstract. Drug-induced aseptic meningitis (DIAM) is a rare but important and often challenging diagnosis for the physician. Intake of antimicrobials, steroids, anal- gesics amongst others has been implicated. Signs and symptoms generally develop within 24-48 hours of drug ingestion. The pa- tient often ...

  1. Contrast induced nephropathy

    DEFF Research Database (Denmark)

    Stacul, Fulvio; van der Molen, Aart J; Reimer, Peter

    2011-01-01

    PURPOSE: The Contrast Media Safety Committee (CMSC) of the European Society of Urogenital Radiology (ESUR) has updated its 1999 guidelines on contrast medium-induced nephropathy (CIN). AREAS COVERED: Topics reviewed include the definition of CIN, the choice of contrast medium, the prophylactic me...

  2. Radiation-induced pneumothorax

    International Nuclear Information System (INIS)

    Epstein, D.M.; Littman, P.; Gefter, W.B.; Miller, W.T.; Raney, R.B. Jr.

    1983-01-01

    Pneumothorax is an uncommon complication of radiation therapy to the chest. The proposed pathogenesis is radiation-induced fibrosis promoting subpleural bleb formation that ruptures resulting in pneumothorax. We report on two young patients with primary sarcomas without pulmonary metastases who developed spontaneous pneumothorax after irradiation. Neither patient had antecedent radiographic evidence of pulmonary fibrosis

  3. Irradiation-Induced Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Birtcher, R.C.; Ewing, R.C.; Matzke, Hj.; Meldrum, A.; Newcomer, P.P.; Wang, L.M.; Wang, S.X.; Weber, W.J.

    1999-08-09

    This paper summarizes the results of the studies of the irradiation-induced formation of nanostructures, where the injected interstitials from the source of irradiation are not major components of the nanophase. This phenomena has been observed by in situ transmission electron microscopy (TEM) in a number of intermetallic compounds and ceramics during high-energy electron or ion irradiations when the ions completely penetrate through the specimen. Beginning with single crystals, electron or ion irradiation in a certain temperature range may result in nanostructures composed of amorphous domains and nanocrystals with either the original composition and crystal structure or new nanophases formed by decomposition of the target material. The phenomenon has also been observed in natural materials which have suffered irradiation from the decay of constituent radioactive elements and in nuclear reactor fuels which have been irradiated by fission neutrons and other fission products. The mechanisms involved in the process of this nanophase formation are discussed in terms of the evolution of displacement cascades, radiation-induced defect accumulation, radiation-induced segregation and phase decomposition, as well as the competition between irradiation-induced amorphization and recrystallization.

  4. Lupus induced by medicaments

    International Nuclear Information System (INIS)

    Canas D, Carlos Alberto; Perafan B, Pablo Eduardo

    2001-01-01

    We describe a 55 years old female patient who consulted by fever syndrome, artralgias and the presence of high tittles positives antinuclear antibodies. She had arterial hypertension in treatment with captopril. We suspected the clinical diagnoses of drug-induced lupus; the withdraw of captopril was associated with the remission of the clinical and laboratory manifestations

  5. Glucocorticoid-induced hyperglycaemia

    NARCIS (Netherlands)

    Gerards, M.C.

    2018-01-01

    This thesis contains studies on current practice, clinical implications and treatment of excess glucocorticoid receptor (GCR) stimulation, with a focus on glucocorticoid-induced hyperglycaemia (GCIH). Chapter 1 is a general introduction to the glucocorticoid hormone. In chapter 2 , we have

  6. Understanding induced seismicity

    NARCIS (Netherlands)

    Elsworth, Derek; Spiers, Christopher J.|info:eu-repo/dai/nl/304829323; Niemeijer, Andre R.|info:eu-repo/dai/nl/370832132

    2016-01-01

    Fluid injection–induced seismicity has become increasingly widespread in oil- and gas-producing areas of the United States (1–3) and western Canada. It has shelved deep geothermal energy projects in Switzerland and the United States (4), and its effects are especially acute in Oklahoma, where

  7. Geomagnetism and Induced Voltage

    Science.gov (United States)

    Abdul-Razzaq, W.; Biller, R. D.

    2010-01-01

    Introductory physics laboratories have seen an influx of "conceptual integrated science" over time in their classrooms with elements of other sciences such as chemistry, biology, Earth science, and astronomy. We describe a laboratory to introduce this development, as it attracts attention to the voltage induced in the human brain as it…

  8. INDUCED ABORTION IN NIGERIA

    African Journals Online (AJOL)

    2014-06-01

    Jun 1, 2014 ... 95% of women would have had an induced abortion. (10), which ... who were fluent in both English and the local language were chosen ... the woman and society. The Muslims ... that “traditional methods are only effective at the early stages of ... modern and traditional family planning services. However ...

  9. Advertising-Induced Embarrassment

    NARCIS (Netherlands)

    Puntoni, S.; Hooge, de I.E.; Verbeke, W.J.M.I.

    2015-01-01

    Abstract Consumer embarrassment is a concern for many advertisers. Yet little is known about ad-induced embarrassment. The authors investigate when and why consumers experience embarrassment as a result of exposure to socially sensitive advertisements. The theory distinguishes between viewing

  10. Forgotten but Not Gone! Syphilis Induced Tenosynovitis

    Directory of Open Access Journals (Sweden)

    Felicia Ratnaraj

    2016-01-01

    Full Text Available Objective. Tenosynovitis, inflammation of a tendon and its synovial sheath, is a rare manifestation of secondary syphilis and if diagnosed early is reversible. Background. A 52-year-old male with past medical history of untreated syphilis presented with gradual onset of swelling and pain of the right fourth metacarpophalangeal joint (MCP. He reported a history of painless penile lesions after having sexual intercourse with a new partner approximately five months ago which was treated with sulfamethoxazole/trimethoprim. An RPR done at that time came back positive with a high titer; however, patient was lost to follow-up. On examination, patient had an edematous, nonerythematous right fourth proximal interphalangeal (PIP joint. Urgent irrigation, debridement, and exploration of the right hand into the tendon sheath were performed. With his history of syphillis, an RPR was done, which was reactive with a titer of 1 : 64. A confirmatory FTA-ABS test was completed, rendering a positive result. Based on his history of untreated syphilis, dormancy followed by clinical scenario of swelling of the right fourth finger, and a high RPR titer, he was diagnosed with secondary syphilis manifesting as tenosynovitis.

  11. Uterine contraction induced by Tanzanian plants used to induce abortion

    DEFF Research Database (Denmark)

    Nikolajsen, Tine; Nielsen, Frank; Rasch, Vibeke

    2011-01-01

    Women in Tanzania use plants to induce abortion. It is not known whether the plants have an effect.......Women in Tanzania use plants to induce abortion. It is not known whether the plants have an effect....

  12. [Hydroxyurea-induced pneumonia].

    Science.gov (United States)

    Girard, A; Ricordel, C; Poullot, E; Claeyssen, V; Decaux, O; Desrues, B; Delaval, P; Jouneau, S

    2014-05-01

    Hydroxyurea is an antimetabolite drug used in the treatment of myeloproliferative disorders. Common adverse effects include haematological, gastrointestinal cutaneous manifestations, and fever. Hydroxyurea-induced pneumonitis is unusual. A female patient was treated with hydroxyurea for polycythemia vera. She was admitted 20 days after commencing treatment with a high fever, productive cough, clear sputum and nausea. A chest CT-scan showed diffuse ground-glass opacities. Microbiological investigations were negative. The symptoms disappeared a few days after discontinuation of the drug and rechallenge led to a relapse of symptoms. Our case and 15 earlier cases of hydroxyurea-induced pneumonitis are reviewed. Two patterns of this disease may exist: an acute febrile form occurring within 1 month of introduction of hydroxyurea and a subacute form without fever. Even if uncommon, one should be aware of this complication of hydroxyurea. Copyright © 2013. Published by Elsevier Masson SAS.

  13. Hydroxychloroquine-induced erythroderma.

    Science.gov (United States)

    Pai, Sunil B; Sudershan, Bhuvaneshwari; Kuruvilla, Maria; Kamath, Ashwin; Suresh, Pooja K

    2017-01-01

    Erythroderma is characterized by diffuse erythema and scaling of the skin involving more than 90% of the total body skin surface area. Drug-induced erythroderma has rarely been reported with hydroxychloroquine. We report a case of a 50-year-old female patient, with systemic lupus erythematosus, who developed itchy lesions all over the body 1 month after starting treatment with hydroxychloroquine. Drug-induced erythroderma was suspected. Hydroxychloroquine was withdrawn and the patient was treated with emollients, mid-potency corticosteroids, and oral antihistamines. A biopsy was done which confirmed the diagnosis of erythroderma. She recovered with treatment and was discharged. A careful history and clinical examination to search for potential causative factors will help prevent disabling sequelae in erythroderma.

  14. Mild induced hypothermia

    DEFF Research Database (Denmark)

    Johansen, Maria E; Jensen, Jens-Ulrik; Bestle, Morten H

    2014-01-01

    INTRODUCTION: Coagulopathy associates with poor outcome in sepsis. Mild induced hypothermia has been proposed as treatment in sepsis but it is not known whether this intervention worsens functional coagulopathy. MATERIALS AND METHODS: Interim analysis data from an ongoing randomized controlled...... trial; The Cooling And Surviving Septic shock (CASS) study. Patients suffering severe sepsis/septic shock are allocated to either mild induced hypothermia (cooling to 32-34°C for 24hours) or control (uncontrolled temperature). TRIAL REGISTRATION: NCT01455116. Thrombelastography (TEG) is performed three....... At enrollment, 3%, 38%, and 59% had a hypocoagulable, normocoagulable, and hypercoagulable TEG clot strength (MA), respectively. In the hypothermia group, functional coagulopathy improved during the hypothermia phase, measured by R and MA, in patients with hypercoagulation as well as in patients...

  15. Time Domain Induced Polarization

    DEFF Research Database (Denmark)

    Fiandaca, Gianluca; Auken, Esben; Christiansen, Anders Vest

    2012-01-01

    Time-domain-induced polarization has significantly broadened its field of reference during the last decade, from mineral exploration to environmental geophysics, e.g., for clay and peat identification and landfill characterization. Though, insufficient modeling tools have hitherto limited the use...... of time-domaininduced polarization for wider purposes. For these reasons, a new forward code and inversion algorithm have been developed using the full-time decay of the induced polarization response, together with an accurate description of the transmitter waveform and of the receiver transfer function......, to reconstruct the distribution of the Cole-Cole parameters of the earth. The accurate modeling of the transmitter waveform had a strong influence on the forward response, and we showed that the difference between a solution using a step response and a solution using the accurate modeling often is above 100...

  16. Topiramate Induced Excessive Sialorrhea

    Directory of Open Access Journals (Sweden)

    Ersel Dag

    2015-11-01

    Full Text Available It is well-known that drugs such as clozapine and lithium can cause sialorrhea. On the other hand, topiramate has not been reported to induce sialorrhea. We report a case of a patient aged 26 who was given antiepileptic and antipsychotic drugs due to severe mental retardation and intractable epilepsy and developed excessive sialorrhea complaint after the addition of topiramate for the control of seizures. His complaints continued for 1,5 years and ended after giving up topiramate. We presented this case since it was a rare sialorrhea case induced by topiramate. Clinicians should be aware of the possibility of sialorrhea development which causes serious hygiene and social problems when they want to give topiramate to the patients using multiple drugs.

  17. Noise-Induced Hearing Loss

    Science.gov (United States)

    ... Home » Health Info » Hearing, Ear Infections, and Deafness Noise-Induced Hearing Loss On this page: What is ... I find additional information about NIHL? What is noise-induced hearing loss? Every day, we experience sound ...

  18. Induced quantum torsion

    International Nuclear Information System (INIS)

    Denardo, G.; Spallucci, E.

    1985-07-01

    We study pregeometry in the framework of a Poincare gauge field theory. The Riemann-Cartan space-time is shown to be an ''effective geometry'' for this model in the low energy limit. By using Heat Kernel techniques we find the induced action for curvature and torsion. We obtain in this way the usual Einstein-Hilbert action plus an axial Maxwell term describing the propagation of a massless, axial vector torsion field. (author)

  19. Cisplatin Induced Nephrotoxicity

    Directory of Open Access Journals (Sweden)

    Seyed Seifollah Beladi Mousavi

    2014-02-01

    The standard approach to prevent cisplatin-induced nephrotoxicity is the administration of lower doses of cisplatin in combination with the administration of full intravenous isotonic saline before and after cisplatin administration. Although a number of pharmacologic agents including sodium thiosulfate, N-acetylcysteine, theophylline and glycine have been evaluated for prevention of nephrotoxicity, none have proved to have an established role, thus, additional clinical studies will be required to confirm their probable effects.

  20. Amitriptyline induced cervical dystonia

    Directory of Open Access Journals (Sweden)

    Shivanand B Hiremath

    2016-01-01

    Full Text Available Tricyclic antidepressants (TCAs, such as amitriptyline, have many side effects. But extrapyramidal tract symptom is an uncommon side effect of these drugs. Here, we report a case of a 28-year-old male who is suffering from amitriptyline induced cervical dystonia. Though rare, this side effect is an uncomfortable condi