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1

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

PubMed Central

Background 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. Results 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. Conclusions 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. PMID:20144228

2010-01-01

2

Physiological correlations and bud dormancy in the apple tree (Malus domestica Borkh.)  

E-print Network

Physiological correlations and bud dormancy in the apple tree (Malus domestica Borkh.) O. Bailly J Introduction During their autumn rest period, terminal and axillary buds of apple trees exhibit dif- ferent buds in apple could be responsible for the shallow dormancy exhibited by these buds. Never- theless

Boyer, Edmond

3

Transcriptome analysis of chestnut (Castanea sativa) tree buds suggests a putative role for epigenetic control of bud dormancy  

PubMed Central

Background and Aims Recent papers indicated that epigenetic control is involved in transitions in bud dormancy, purportedly controlling gene expression. The present study aimed to identify genes that are differentially expressed in dormant and non-dormant Castanea sativa buds. Methods Two suppression subtractive hybridization cDNA libraries were constructed to characterize the transcriptomes of dormant apical buds of C. sativa, and buds in which dormancy was released. Key Results A total of 512 expressed sequence tags (ESTs) were generated in a forward and reverse subtractive hybridization experiment. Classification of these ESTs into functional groups demonstrated that dormant buds were predominantly characterized by genes associated with stress response, while non-dormant buds were characterized by genes associated with energy, protein synthesis and cellular components for development and growth. ESTs for a few genes involved in different forms of epigenetic modification were found in both libraries, suggesting a role for epigenetic control in bud dormancy different from that in growth. Genes encoding histone mono-ubiquitinase HUB2 and histone acetyltransferase GCN5L were associated with dormancy, while a gene encoding histone H3 kinase AUR3 was associated with growth. Real-time RT-PCR with a selection of genes involved in epigenetic modification and stress tolerance confirmed the expression of the majority of investigated genes in various stages of bud development, revealing a cyclical expression pattern concurring with the growth seasons for most genes. However, senescing leaves also showed an increased expression of several of the genes associated with dormancy, implying pleiotropy. Furthermore, a comparison between these subtraction cDNA libraries and the poplar bud dormancy transcriptome and arabidopsis transcriptomes for seed dormancy and non-dormancy indicated a common basis for dormancy in all three systems. Conclusions Bud dormancy and non-dormancy in C. sativa were characterized by distinct sets of genes and are likely to be under different epigenetic control. PMID:21803738

Santamaría, María Estrella; Rodríguez, Roberto; Cañal, María Jesús; Toorop, Peter E.

2011-01-01

4

Ethanol breaks dormancy of the potato tuber apical bud.  

PubMed

Growing potato tubers or freshly harvested mature tubers have a dormant apical bud. Normally, this dormancy is spontaneously broken after a period of maturation of the tuber, resulting in the growth of a new sprout. Here it is shown that in in vitro-cultured growing and maturing tubers, ethanol can rapidly break this dormancy and re-induce growth of the apical bud. The in vivo promoter activity of selected genes during this secondary growth of the apical bud was monitored, using luciferase as a reporter. In response to ethanol, the expression of carbohydrate-storage, protein-storage, and cell division-related genes are rapidly down-regulated in tuber tissue. It was shown that dormancy was broken by primary but not by secondary alcohols, and the effect of ethanol on sprouting and gene expression in tuber tissue was blocked by an inhibitor of alcohol dehydrogenase. By contrast, products derived from alcohol dehydrogenase activity (acetaldehyde and acetic acid) did not induce sprouting, nor did they affect luciferase reporter gene activity in the tuber tissue. Application of an inhibitor of gibberellin biosynthesis had no effect on ethanol-induced sprouting. It is suggested that ethanol-induced sprouting may be related to an alcohol dehydrogenase-mediated increase in the catabolic redox charge [NADH/(NADH+NAD+)]. PMID:16043450

Claassens, Margo M J; Verhees, John; van der Plas, Linus H W; van der Krol, Alexander R; Vreugdenhil, Dick

2005-09-01

5

A Molecular Timetable for Apical Bud Formation and Dormancy Induction in Poplar[W  

PubMed Central

The growth of perennial plants in the temperate zone alternates with periods of dormancy that are typically initiated during bud development in autumn. In a systems biology approach to unravel the underlying molecular program of apical bud development in poplar (Populus tremula × Populus alba), combined transcript and metabolite profiling were applied to a high-resolution time course from short-day induction to complete dormancy. Metabolite and gene expression dynamics were used to reconstruct the temporal sequence of events during bud development. Importantly, bud development could be dissected into bud formation, acclimation to dehydration and cold, and dormancy. To each of these processes, specific sets of regulatory and marker genes and metabolites are associated and provide a reference frame for future functional studies. Light, ethylene, and abscisic acid signal transduction pathways consecutively control bud development by setting, modifying, or terminating these processes. Ethylene signal transduction is positioned temporally between light and abscisic acid signals and is putatively activated by transiently low hexose pools. The timing and place of cell proliferation arrest (related to dormancy) and of the accumulation of storage compounds (related to acclimation processes) were established within the bud by electron microscopy. Finally, the identification of a large set of genes commonly expressed during the growth-to-dormancy transitions in poplar apical buds, cambium, or Arabidopsis thaliana seeds suggests parallels in the underlying molecular mechanisms in different plant organs. PMID:17693531

Ruttink, Tom; Arend, Matthias; Morreel, Kris; Storme, Véronique; Rombauts, Stephane; Fromm, Jörg; Bhalerao, Rishikesh P.; Boerjan, Wout; Rohde, Antje

2007-01-01

6

Effects of dormancy and environmental factors on timing of bud burst in Betula pendula  

Microsoft Academic Search

Summary We tested three theories predicting the timing of bud burst in mature birch ( Betula pendula Roth) trees utilizing a 60-year phenological time series together with meteorologi - cal temperature observations. Predictions of the timing of bud burst based on light conditions in addition to temperature were more accurate than predictions based on dormancy develop- ment and temperature (prediction

RISTO HÄKKINEN; TAPIO LINKOSALO; PERTTI HARI

7

Chilling-Dependent Release of Seed and Bud Dormancy in Peach Associates to Common Changes in Gene Expression  

PubMed Central

Reproductive meristems and embryos display dormancy mechanisms in specialized structures named respectively buds and seeds that arrest the growth of perennial plants until environmental conditions are optimal for survival. Dormancy shows common physiological features in buds and seeds. A genotype-specific period of chilling is usually required to release dormancy by molecular mechanisms that are still poorly understood. In order to find common transcriptional pathways associated to dormancy release, we analyzed the chilling-dependent expression in embryos of certain genes that were previously found related to dormancy in flower buds of peach. We propose the presence of short and long-term dormancy events affecting respectively the germination rate and seedling development by independent mechanisms. Short periods of chilling seem to improve germination in an abscisic acid-dependent manner, whereas the positive effect of longer cold treatments on physiological dwarfing coincides with the accumulation of phenylpropanoids in the seed. PMID:22590512

Arbona, Vicent; Gómez-Cadenas, Aurelio; Llácer, Gerardo; Badenes, María Luisa; Ríos, Gabino

2012-01-01

8

Differential expression of proteins associated with seasonal bud dormancy at four critical stages in Japanese apricot.  

PubMed

Dormancy is of great significance in the growth and development of deciduous fruit trees. We used a combination of two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionisation time of flight/time of flight mass spectrometry (MALDI-TOF/TOF MS) to identify the differentially expressed proteome of Japanese apricot flower buds at four critical stages, from paradormancy before leaf fall to dormancy release. More than 400 highly reproducible protein spots (P < 0.05) were detected: 34 protein spots showed a greater than twofold difference in expression values, of which 32 protein spots were confidently identified from databases. Identified proteins were classified into six functional categories: stress response and defence (11), energy metabolism (ten), protein metabolism (five), cell structure (three), transcription (one) and unclassified (two). The glyoxalase I homologue could help Japanese apricot survival under various abiotic and biotic stresses, greatly contributing to its dormancy. Enolase, thioredoxin family proteins and triose phosphate isomerase provide adequate energy to complete consecutive dormancy release and bud break in Japanese apricot. Cinnamyl alcohol dehydrogenase 9 and arginase enhance the resilience of plants, enabling them to complete dormancy safely. Analysis of functions of identified proteins and related metabolic pathways will increase our knowledge of dormancy in woody plants. PMID:22672637

Zhuang, W-B; Shi, T; Gao, Z-H; Zhang, Z; Zhang, J-Y

2013-01-01

9

Symplastic connection is required for bud outgrowth following dormancy in potato (Solanum tuberosum L.) tubers.  

PubMed

To gain greater insight into the mechanism of dormancy release in the potato tuber, an investigation into physiological and biochemical changes in tuber and bud tissues during the transition from bud dormancy (immediately after harvest) to active bud growth was undertaken. Within the tuber, a rapid shift from storage metabolism (starch synthesis) to reserve mobilization within days of detachment from the mother plant suggested transition from sink to source. Over the same period, a shift in the pattern of [U-(14)C]sucrose uptake by tuber discs from diffuse to punctate accumulation was consistent with a transition from phloem unloading to phloem loading within the tuber parenchyma. There were no gross differences in metabolic capacity between resting and actively growing tuber buds as determined by [U-(14)C]glucose labelling. However, marked differences in metabolite pools were observed with large increases in starch and sucrose, and the accumulation of several organic acids in growing buds. Carboxyfluorescein labelling of tubers clearly demonstrated strong symplastic connection in actively growing buds and symplastic isolation in resting buds. It is proposed that potato tubers rapidly undergo metabolic transitions consistent with bud outgrowth; however, growth is initially prevented by substrate limitation mediated via symplastic isolation. PMID:17617825

Viola, Roberto; Pelloux, Jérôme; van der Ploeg, Anke; Gillespie, Trudi; Marquis, Nicola; Roberts, Alison G; Hancock, Robert D

2007-08-01

10

Molecular Analysis of Signals Controlling Dormancy and Growth in Underground Adventitious Buds of Leafy Spurge  

Microsoft Academic Search

Dormancy and subsequent regrowth of adventitious buds is a critical physiological process for many perennial plants. We have used the expression of hormone and cell cycle-responsive genes as markers to follow this process in leafy spurge (Euphorbia esula). In conjunction with earlier studies, we show that loss of mature leaves results in decreased sugar levels and increased gibberellin perception in

David P. Horvath; Wun S. Chao; James V. Anderson

2002-01-01

11

Changes in well-defined phases of bud dormancy associated with shifts in carbohydrate metabolism may involve beta-amylases  

Technology Transfer Automated Retrieval System (TEKTRAN)

Leafy spurge is a noxious perennial weed that infests range lands in the Northern Great Plains. It is being used as a model to investigate dormancy in underground adventitious buds, i.e., root and crown buds. Underground adventitious buds of leafy spurge (Euphorbia esula) are 1) maintained in a quie...

12

Relationships among cold hardiness, root growth potential and bud dormancy in three conifers.  

PubMed

Greenhouse-cultured, container-grown ponderosa pine (Pinus ponderosa var. scopulorum Engelm.), interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and Engelmann spruce (Picea engelmannii (Parry) Engelm.) were cold acclimated and deacclimated in growth chambers over 19 weeks. Stem cold hardiness, total new root length at 14 days and days to bud break were measured weekly. Relationships among cold hardiness, root growth potential (RGP) and bud dormancy suggest that cold hardiness, which can be measured quickly, could provide a useful basis for estimating the two other parameters. During cold acclimation, there was a lag period in which stem cold hardiness remained at -15 degrees C and RGP was at a minimum, in all three species. Douglas-fir and Engelmann spruce buds remained fully dormant during this lag period. Ponderosa pine buds had no chilling requirement for the loss of dormancy, and reached quiescence during the lag period. Immediately following the lag period, as stem cold hardiness progressed to -22 degrees C, RGP increased to a high plateau in all three species, and Douglas-fir and Engelmann spruce buds approached quiescence. Cold deacclimation and bud development began immediately on exposure to warm, long days, but RGP remained high until stem cold hardiness returned to approximately -15 degrees C. At bud break, cold hardiness and RGP were at the minimum. PMID:14972975

Burr, K E; Tinus, R W; Wallner, S J; King, R M

1989-09-01

13

Effects of "near-lethal" stress on bud dormancy and stem cold hardiness in red-osier dogwood.  

PubMed

We studied the effects of "near-lethal" (NL, 47 degrees C for 1 h) heat stress, applied to intact shoots of red-osier dogwood (Cornus sericea L.) during early (October), deep (November) or late (December) dormancy, on bud dormancy release and development of stem tissue cold hardiness under natural conditions and at a constant temperature of 0 or 23 degrees C in the dark. The NL heat-stress treatment overcame bud dormancy when applied during the early and late stages of dormancy. During October and December, all plants in the 23 degrees C + dark post-stress environment broke bud within 35 and 12 days, respectively, whereas the corresponding values for days to bud break in the control plants were more than 150 and 110 days, respectively. Application of NL heat stress during deep dormancy caused only slightly earlier bud break compared to the control plants. In the 0 degrees C + dark post-stress environment, all NL heat-treated plants died within 9 weeks. Under natural post-stress conditions, bud break in plants receiving NL heat stress during early and deep dormancy occurred at the same time as in control plants, whereas bud break of plants receiving NL heat stress during late dormancy occurred 55 days earlier than in control plants. Under both natural and 23 degrees C + dark post-stress conditions, cold hardiness of plants receiving NL heat stress during early dormancy was similar to that of controls. Application of NL heat stress during deep dormancy hastened the rate of deacclimation under the 23 degrees C + dark post-stress conditions but had no effect on deacclimation under natural post-stress conditions. Application of NL heat stress during late dormancy enhanced deacclimation of plants in both the 23 degrees C + dark and natural post-stress environments. PMID:14965968

Shirazi, A M; Fuchigami, L H

1995-04-01

14

Candidate genes associated with bud dormancy release in blackcurrant (Ribes nigrum L.)  

PubMed Central

Background The detrimental effects of mild winter temperatures on the consistency of cropping of blackcurrant (Ribes nigrum L.) in parts of Europe have led to increasing interest in the genetic control of dormancy release in this species. This study examined patterns of gene expression in leaf buds of blackcurrant to identify key differential changes in these profiles around the time of budbreak. Results Using leaf bud tissue of blackcurrant, a cDNA library was generated as a source of blackcurrant ESTs for construction of a custom microarray, which was used to identify differential gene expression during dormancy release. Gene activity was lowest in early stages of dormancy, increasing to reach a maximum around the time of budbreak. Genes with significantly changing expression profiles were clustered and evidence is provided for the transient activity of genes previously associated with dormancy processes in other species. Expression profiling identified candidate genes which were mapped onto a blackcurrant genetic linkage map containing budbreak-related QTL. Three genes, which putatively encode calmodulin-binding protein, beta tubulin and acetyl CoA carboxylase respectively, were found to co-localise with budbreak QTL. Conclusions This study provides insight into the genetic control of dormancy transition in blackcurrant, identifying key changes in gene expression around budbreak. Genetic mapping of ESTs enabled the identification of genes which co-localise with previously-characterised blackcurrant QTL, and it is concluded that these genes have probable roles in release of dormancy and can therefore provide a basis for the development of genetic markers for future breeding deployment. PMID:20840772

2010-01-01

15

Low temperatures impact dormancy status, flowering competence, and transcript profiles in crown buds of leafy spurge  

Microsoft Academic Search

Leafy spurge (Euphorbia esula) is an herbaceous perennial weed that produces vegetatively from an abundance of underground adventitious buds. In this study,\\u000a we report the effects of different environmental conditions on vegetative production and flowering competence, and determine\\u000a molecular mechanisms associated with dormancy transitions under controlled conditions. Reduction in temperature (27–10°C)\\u000a and photoperiod (16–8 h) over a 3-month period induced a

Münevver Do?ramac?; David P. Horvath; Wun S. Chao; Michael E. Foley; Michael J. Christoffers; James V. Anderson

2010-01-01

16

The control of bud dormancy in potato tubers : Evidence for the primary role of cytokinins and a seasonal pattern of changing sensitivity to cytokinin.  

PubMed

Potato (Solanum tuberosum L.) tuber buds normally remain dormant through the growing season until several weeks after harvest. In the cultivar Majestic, this innate dormancy persisted for 9 to 12 weeks in storage at 10° C, but only 3 to 4 weeks when the tubers were stored at 2° C. At certain stages, supplying cytokinins to tubers with innately dormant buds induced sprout growth within 2 d. The growth rate was comparable to that of buds whose innate dormancy had been lost naturally. Cytokinin-treatment did not accelerate the rates of cell division and cell expansion in buds whose innate dormancy had already broken naturally. Gibberellic acid did not induce sprout growth in buds with innate dormancy. We conclude that cytokinins may well be the primary factor in the switch from innate dormancy to the non-dormant state in potato tuber buds, but probably do not control the subsequent sprout growth. PMID:24241141

Turnbull, C G; Hanke, D E

1985-08-01

17

The control of bud dormancy in potato tubers. Measurement of the seasonal pattern of changing concentrations of zeatin-cytokinins.  

PubMed

A radioimmunoassay, combined with high-performance liquid chromatography, has been used to analyse the zeatin-type cytokinins of potato (Solanum tuberosum L. cv. Majestic) tubers and tuber buds throughout growth and storage. During tuber growth, zeatin riboside was the predominant cytokinin detected in all tissues. Immediately after harvest, the total cytokinin concentration fell dramatically in the storage tissue, largely as a consequence of the disappearance of zeatin riboside. During storage, levels of cytokinins in the storage tissue remained relatively constant, but increased in the tuber buds. In the buds of tubers stored at 2°C there was a 20-to 50-fold increase in total cytokinin over six weeks, coinciding with the natural break of innate dormancy. At 10°C the rise in the level of bud cytokinins was slower, correlating with the longer duration of innate dormancy. Injecting unlabelled cytokinins into tubers in amounts known to induce sprouting gave rise to increases in cytokinin concentrations in the buds of the same order as the increase associated with the natural break of dormancy. Metabolism of injected cytokinins was greater in non-dormant than in dormant tubers. The roles of cytokinin concentration and the sensitivity of the buds to cytokinin in the control of dormancy are discussed. PMID:24241142

Turnbull, C G; Hanke, D E

1985-08-01

18

Seasonal shifts in dormancy status, carbohydrate metabolism, and related gene expression in crown buds of leafy spurge  

Microsoft Academic Search

Crown buds of field-grown leafy spurge ( Euphorbia esula L.) were examined to determine relationships between car- bohydrate metabolism and gene expression throughout para-, endo-, and eco-dormancy during the transition from summer, autumn, and winter, respectively. The data indi- cates that endo-dormancy plays a role in preventing new shoot growth during the transition from autumn to winter. Cold temperature was

JAMES V. ANDERSON; RUSS W. GESCH; YING JIA; WUN S. CHAO; DAVID P. HORVATH

2005-01-01

19

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

PubMed Central

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. PMID:23234335

2012-01-01

20

Transcriptional profiling of bud dormancy induction and release in oak by next-generation sequencing  

PubMed Central

Background In temperate regions, the time lag between vegetative bud burst and bud set determines the duration of the growing season of trees (i.e. the duration of wood biomass production). Dormancy, the period during which the plant is not growing, allows trees to avoid cold injury resulting from exposure to low temperatures. An understanding of the molecular machinery controlling the shift between these two phenological states is of key importance in the context of climatic change. The objective of this study was to identify genes upregulated during endo- and ecodormancy, the two main stages of bud dormancy. Sessile oak is a widely distributed European white oak species. A forcing test on young trees was first carried out to identify the period most likely to correspond to these two stages. Total RNA was then extracted from apical buds displaying endo- and ecodormancy. This RNA was used for the generation of cDNA libraries, and in-depth transcriptome characterization was performed with 454 FLX pyrosequencing technology. Results Pyrosequencing produced a total of 495,915 reads. The data were cleaned, duplicated reads removed, and sequences were mapped onto the oak UniGene data. Digital gene expression analysis was performed, with both R statistics and the R-Bioconductor packages (edgeR and DESeq), on 6,471 contigs with read numbers ? 5 within any contigs. The number of sequences displaying significant differences in expression level (read abundance) between endo- and ecodormancy conditions ranged from 75 to 161, depending on the algorithm used. 13 genes displaying significant differences between conditions were selected for further analysis, and 11 of these genes, including those for glutathione-S-transferase (GST) and dehydrin xero2 (XERO2) were validated by quantitative PCR. Conclusions The identification and functional annotation of differentially expressed genes involved in the “response to abscisic acid”, “response to cold stress” and “response to oxidative stress” categories constitutes a major step towards characterization of the molecular network underlying vegetative bud dormancy, an important life history trait of long-lived organisms. PMID:23575249

2013-01-01

21

EARLY BUD-BREAK 1 (EBB1) is a regulator of release from seasonal dormancy in poplar trees  

PubMed Central

Trees from temperate latitudes transition between growth and dormancy to survive dehydration and freezing stress during winter months. We used activation tagging to isolate a dominant mutation affecting release from dormancy and identified the corresponding gene EARLY BUD-BREAK 1 (EBB1). We demonstrate through positioning of the tag, expression analysis, and retransformation experiments that EBB1 encodes a putative APETALA2/Ethylene responsive factor transcription factor. Transgenic up-regulation of the gene caused early bud-flush, whereas down-regulation delayed bud-break. Native EBB1 expression was highest in actively growing apices, undetectable during the dormancy period, but rapidly increased before bud-break. The EBB1 transcript was localized in the L1/L2 layers of the shoot meristem and leaf primordia. EBB1-overexpressing transgenic plants displayed enlarged shoot meristems, open and poorly differentiated buds, and a higher rate of cell division in the apex. Transcriptome analyses of the EBB1 transgenics identified 971 differentially expressed genes whose expression correlated with the EBB1 expression changes in the transgenic plants. Promoter analysis among the differentially expressed genes for the presence of a canonical EBB1-binding site identified 65 putative target genes, indicative of a broad regulatory context of EBB1 function. Our results suggest that EBB1 has a major and integrative role in reactivation of meristem activity after winter dormancy. PMID:24951507

Yordanov, Yordan S.; Ma, Cathleen; Strauss, Steven H.; Busov, Victor B.

2014-01-01

22

EARLY BUD-BREAK 1 (EBB1) is a regulator of release from seasonal dormancy in poplar trees.  

PubMed

Trees from temperate latitudes transition between growth and dormancy to survive dehydration and freezing stress during winter months. We used activation tagging to isolate a dominant mutation affecting release from dormancy and identified the corresponding gene EARLY BUD-BREAK 1 (EBB1). We demonstrate through positioning of the tag, expression analysis, and retransformation experiments that EBB1 encodes a putative APETALA2/Ethylene responsive factor transcription factor. Transgenic up-regulation of the gene caused early bud-flush, whereas down-regulation delayed bud-break. Native EBB1 expression was highest in actively growing apices, undetectable during the dormancy period, but rapidly increased before bud-break. The EBB1 transcript was localized in the L1/L2 layers of the shoot meristem and leaf primordia. EBB1-overexpressing transgenic plants displayed enlarged shoot meristems, open and poorly differentiated buds, and a higher rate of cell division in the apex. Transcriptome analyses of the EBB1 transgenics identified 971 differentially expressed genes whose expression correlated with the EBB1 expression changes in the transgenic plants. Promoter analysis among the differentially expressed genes for the presence of a canonical EBB1-binding site identified 65 putative target genes, indicative of a broad regulatory context of EBB1 function. Our results suggest that EBB1 has a major and integrative role in reactivation of meristem activity after winter dormancy. PMID:24951507

Yordanov, Yordan S; Ma, Cathleen; Strauss, Steven H; Busov, Victor B

2014-07-01

23

Comparative proteomic and transcriptomic approaches to address the active role of GA4 in Japanese apricot flower bud dormancy release.  

PubMed

Hormones are closely associated with dormancy in deciduous fruit trees, and gibberellins (GAs) are known to be particularly important. In this study, we observed that GA4 treatment led to earlier bud break in Japanese apricot. To understand better the promoting effect of GA4 on the dormancy release of Japanese apricot flower buds, proteomic and transcriptomic approaches were used to analyse the mechanisms of dormancy release following GA4 treatment, based on two-dimensional gel electrophoresis (2-DE) and digital gene expression (DGE) profiling, respectively. More than 600 highly reproducible protein spots (P<0.05) were detected and, following GA4 treatment, 38 protein spots showed more than a 2-fold difference in expression, and 32 protein spots were confidently identified according to the databases. Compared with water treatment, many proteins that were associated with energy metabolism and oxidation-reduction showed significant changes after GA4 treatment, which might promote dormancy release. We observed that genes at the mRNA level associated with energy metabolism and oxidation-reduction also played an important role in this process. Analysis of the functions of the identified proteins and genes and the related metabolic pathways would provide a comprehensive proteomic and transcriptomic view of the coordination of dormancy release after GA4 treatment in Japanese apricot flower buds. PMID:24014872

Zhuang, Weibing; Gao, Zhihong; Wang, Liangju; Zhong, Wenjun; Ni, Zhaojun; Zhang, Zhen

2013-11-01

24

Comparative proteomic and transcriptomic approaches to address the active role of GA4 in Japanese apricot flower bud dormancy release  

PubMed Central

Hormones are closely associated with dormancy in deciduous fruit trees, and gibberellins (GAs) are known to be particularly important. In this study, we observed that GA4 treatment led to earlier bud break in Japanese apricot. To understand better the promoting effect of GA4 on the dormancy release of Japanese apricot flower buds, proteomic and transcriptomic approaches were used to analyse the mechanisms of dormancy release following GA4 treatment, based on two-dimensional gel electrophoresis (2-DE) and digital gene expression (DGE) profiling, respectively. More than 600 highly reproducible protein spots (P<0.05) were detected and, following GA4 treatment, 38 protein spots showed more than a 2-fold difference in expression, and 32 protein spots were confidently identified according to the databases. Compared with water treatment, many proteins that were associated with energy metabolism and oxidation–reduction showed significant changes after GA4 treatment, which might promote dormancy release. We observed that genes at the mRNA level associated with energy metabolism and oxidation–reduction also played an important role in this process. Analysis of the functions of the identified proteins and genes and the related metabolic pathways would provide a comprehensive proteomic and transcriptomic view of the coordination of dormancy release after GA4 treatment in Japanese apricot flower buds. PMID:24014872

Zhuang, Weibing; Gao, Zhihong; Zhang, Zhen

2013-01-01

25

Dormancy and spring burst of lateral buds on stems of low-pruned mulberry (Morus alba L.)  

E-print Network

Dormancy and spring burst of lateral buds on stems of low-pruned mulberry (Morus alba L.) T. Suzuki decapitation, lateral shoot growth of mulberry coppice (Morus alba L.) from low-pruned stumps has an extremely. Materials and Methods Rooted hardwood cuttings of Morus alba L. cv. Shin-ichinose were grown in a light clay

Paris-Sud XI, Université de

26

Vernalization and the chilling requirement to exit bud dormancy: shared or separate regulation?  

PubMed Central

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. PMID:25566302

Brunner, Amy M.; Evans, Luke M.; Hsu, Chuan-Yu; Sheng, Xiaoyan

2014-01-01

27

Conservation and divergence of four kiwifruit SVP-like MADS-box genes suggest distinct roles in kiwifruit bud dormancy and flowering  

PubMed Central

MADS-box genes similar to Arabidopsis SHORT VEGETATIVE PHASE (SVP) have been implicated in the regulation of flowering in annual species and bud dormancy in perennial species. Kiwifruit (Actinidia spp.) are woody perennial vines where bud dormancy and out-growth affect flower development. To determine the role of SVP-like genes in dormancy and flowering of kiwifruit, four MADS-box genes with homology to Arabidopsis SVP, designated SVP1, SVP2, SVP3, and SVP4, have been identified and analysed in kiwifruit and functionally characterized in Arabidopsis. Phylogenetic analysis indicate that these genes fall into different sub-clades within the SVP-like gene group, suggesting distinct functions. Expression was generally confined to vegetative tissues, and increased transcript accumulation in shoot buds over the winter period suggests a role for these genes in bud dormancy. Down-regulation before flower differentiation indicate possible roles as floral repressors. Over-expression and complementation studies in Arabidopsis resulted in a range of floral reversion phenotypes arising from interactions with Arabidopsis MADS-box proteins, but only SVP1 and SVP3 were able to complement the svp mutant. These results suggest that the kiwifruit SVP-like genes may have distinct roles during bud dormancy and flowering. PMID:22071267

Wu, Rong-Mei; Walton, Eric F.; Richardson, Annette C.; Wood, Marion; Hellens, Roger P.; Varkonyi-Gasic, Erika

2012-01-01

28

Histone modifications and expression of DAM6 gene in peach are modulated during bud dormancy release in a cultivar-dependent manner.  

PubMed

Bud dormancy release in many woody perennial plants responds to the seasonal accumulation of chilling stimulus. MADS-box transcription factors encoded by DORMANCY ASSOCIATED MADS-box (DAM) genes in peach (Prunus persica) are implicated in this pathway, but other regulatory factors remain to be identified. In addition, the regulation of DAM gene expression is not well known at the molecular level. • A microarray hybridization approach was performed to identify genes whose expression correlates with the bud dormancy-related behaviour in 10 different peach cultivars. Histone modifications in DAM6 gene were investigated by chromatin immunoprecipitation in two different cultivars. • The expression of DAM4-DAM6 and several genes related to abscisic acid and drought stress response correlated with the dormancy behaviour of peach cultivars. The trimethylation of histone H3 at K27 in the DAM6 promoter, coding region and the second large intron was preceded by a decrease in acetylated H3 and trimethylated H3K4 in the region of translation start, coinciding with repression of DAM6 during dormancy release. • Analysis of chromatin modifications reinforced the role of epigenetic mechanisms in DAM6 regulation and bud dormancy release, and highlighted common features with the vernalization process in Arabidopsis thaliana and cereals. PMID:21899556

Leida, Carmen; Conesa, Ana; Llácer, Gerardo; Badenes, María Luisa; Ríos, Gabino

2012-01-01

29

Dose- and tissue-specific interaction of monoterpenes with the gibberellin-mediated release of potato tuber bud dormancy, sprout growth and induction of ?-amylases and ?-amylases.  

PubMed

Gibberellins (GA) are involved in bud dormancy release in several species. We show here that GA-treatment released bud dormancy, initiated bud sprouting and promoted sprout growth of excised potato tuber bud discs ('eyes'). Monoterpenes from peppermint oil (PMO) and S-(+)-carvone (CAR) interact with the GA-mediated bud dormancy release in a hormesis-type response: low monoterpene concentrations enhance dormancy release and the initiation of bud sprouting, whereas high concentrations inhibit it. PMO and CAR did, however, not affect sprout growth rate after its onset. We further show that GA-induced dormancy release is associated with tissue-specific regulation of ?- and ?-amylases. Molecular phylogenetic analysis shows that potato ?-amylases cluster into two distinct groups: ?-AMY1 and ?-AMY2. GA-treatment induced transcript accumulation of members of both ?-amylase groups, as well as ?- and ?-amylase enzyme activity in sprout and 'sub-eye' tissues. In sprouts, CAR interacts with the GA-mediated accumulation of ?-amylase transcripts in an ?-AMY2-specific and dose-dependent manner. Low CAR concentrations enhance the accumulation of ?-AMY2-type ?-amylase transcripts, but do not affect the ?-AMY1-type transcripts. Low CAR concentrations also enhance the accumulation of ?- and ?-amylase enzyme activity in sprouts, but not in 'sub-eye' tissues. In contrast, high CAR concentrations have no appreciable effect in sprouts on the enzyme activities and the ?-amylase transcript abundances of either group. The dose-dependent effects on the enzyme activities and the ?-AMY2-type ?-amylase transcripts in sprouts are specific for CAR but not for PMO. Different monoterpenes therefore may have specific targets for their interaction with hormone signalling pathways. PMID:21858448

Rentzsch, Sonja; Podzimska, Dagmara; Voegele, Antje; Imbeck, Madeleine; Müller, Kerstin; Linkies, Ada; Leubner-Metzger, Gerhard

2012-01-01

30

Gene-expression profiling of grape bud response to two alternative dormancy-release stimuli expose possible links between impaired mitochondrial activity, hypoxia, ethylene-ABA interplay and cell enlargement  

Microsoft Academic Search

A grape-bud-oriented genomic platform was produced for a large-scale comparative analysis of bud responses to two stimuli\\u000a of grape-bud dormancy release, hydrogen cyanamide (HC) and heat shock (HS). The results suggested considerable similarity\\u000a in bud response to the stimuli, both in the repertoire of responding genes and in the temporary nature of the transcriptome\\u000a reprogramming. Nevertheless, the bud response to

Ron Ophir; Xuequn Pang; Tamar Halaly; Jaganatha Venkateswari; Shimon Lavee; David Galbraith; Etti

2009-01-01

31

ptr-MIR169 is a posttranscriptional repressor of PtrHAP2 during vegetative bud dormancy period of aspen (Populus tremuloides) trees  

SciTech Connect

Highlights: ? We show a novel microRNA-mediated mechanism for control of bud dormancy in trees. ? ptr-MIR169a and PtrHAP2–5 gene showed inverse expression during dormancy period. ? The PtrHAP2–5 decline in abundance correlated with high ptr-MIR169a levels. ? PtrHAP2–5 cleavage occurred at the miR169 site during PtrHAP2–5 transcript decline. ? Our results show that miR169 attenuates PtrHAP2–5 transcript during dormancy. -- Abstract: Dormancy is a mechanism evolved in woody perennial plants to survive the winter freezing and dehydration stress via temporary suspension of growth. We have identified two aspen microRNAs (ptr-MIR169a and ptr-MIR169h) which were highly and specifically expressed in dormant floral and vegetative buds. ptr-MIR169a and its target gene PtrHAP2–5 showed inverse expression patterns during the dormancy period. ptr-MIR169a transcript steadily increased through the first half of the dormancy period and gradually declined with the approach of active growing season. PtrHAP2–5 abundance was higher in the beginning of the dormancy period but rapidly declined thereafter. The decline of PtrHAP2–5 correlated with the high levels of ptr-MIR169a accumulation, suggesting miR169-mediated attenuation of the target PtrHAP2–5 transcript. We experimentally verified the cleavage of PtrHAP2–5 at the predicted miR169a site at the time when PtrHAP2–5 transcript decline was observed. HAP2 is a subunit of a nuclear transcription factor Y (NF-Y) complex consisting of two other units, HAP3 and HAP5. Using digital expression profiling we show that poplar HAP2 and HAP5 are preferentially detected in dormant tissues. Our study shows that microRNAs play a significant and as of yet unknown and unstudied role in regulating the timing of bud dormancy in trees.

Potkar, Rewati; Recla, Jill [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)] [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States); Busov, Victor, E-mail: vbusov@mtu.edu [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)] [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)

2013-02-15

32

DNA methylation/demethylation programming during peach flower bud dormancy release, development and blooming  

Technology Transfer Automated Retrieval System (TEKTRAN)

Peach flower bud development undergoes a long, complex and temperature-dependent regulation process with cessation of growth in response to cool temperatures in late fall, a slow but gradual development during the chilling period in winter, and eventually blooming in early spring. It has been demon...

33

BRANCHED1 Promotes Axillary Bud Dormancy in Response to Shade in Arabidopsis[C][W  

PubMed Central

Plants interpret a decrease in the red to far-red light ratio (R:FR) as a sign of impending shading by neighboring vegetation. This triggers a set of developmental responses known as shade avoidance syndrome. One of these responses is reduced branching through suppression of axillary bud outgrowth. The Arabidopsis thaliana gene BRANCHED1 (BRC1), expressed in axillary buds, is required for branch suppression in response to shade. Unlike wild-type plants, brc1 mutants develop several branches after a shade treatment. BRC1 transcription is positively regulated 4 h after exposure to low R:FR. Consistently, BRC1 is negatively regulated by phytochrome B. Transcriptional profiling of wild-type and brc1 buds of plants treated with simulated shade has revealed groups of genes whose mRNA levels are dependent on BRC1, among them a set of upregulated abscisic acid response genes and two networks of cell cycle– and ribosome-related downregulated genes. The downregulated genes have promoters enriched in TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) binding sites, suggesting that they could be transcriptionally regulated by TCP factors. Some of these genes respond to BRC1 in seedlings and buds, supporting their close relationship with BRC1 activity. This response may allow the rapid adaptation of plants to fluctuations in the ratio of R:FR light. PMID:23524661

González-Grandío, Eduardo; Poza-Carrión, César; Sorzano, Carlos Oscar S.; Cubas, Pilar

2013-01-01

34

ptr-MIR169 is a posttranscriptional repressor of PtrHAP2 during vegetative bud dormancy period of aspen (Populus tremuloides) trees.  

PubMed

Dormancy is a mechanism evolved in woody perennial plants to survive the winter freezing and dehydration stress via temporary suspension of growth. We have identified two aspen microRNAs (ptr-MIR169a and ptr-MIR169h) which were highly and specifically expressed in dormant floral and vegetative buds. ptr-MIR169a and its target gene PtrHAP2-5 showed inverse expression patterns during the dormancy period. ptr-MIR169a transcript steadily increased through the first half of the dormancy period and gradually declined with the approach of active growing season. PtrHAP2-5 abundance was higher in the beginning of the dormancy period but rapidly declined thereafter. The decline of PtrHAP2-5 correlated with the high levels of ptr-MIR169a accumulation, suggesting miR169-mediated attenuation of the target PtrHAP2-5 transcript. We experimentally verified the cleavage of PtrHAP2-5 at the predicted miR169a site at the time when PtrHAP2-5 transcript decline was observed. HAP2 is a subunit of a nuclear transcription factor Y (NF-Y) complex consisting of two other units, HAP3 and HAP5. Using digital expression profiling we show that poplar HAP2 and HAP5 are preferentially detected in dormant tissues. Our study shows that microRNAs play a significant and as of yet unknown and unstudied role in regulating the timing of bud dormancy in trees. PMID:23321309

Potkar, Rewati; Recla, Jill; Busov, Victor

2013-02-15

35

Ecological implications of grass bud bank and tiller dynamics in mixed-grass prairie.  

E-print Network

??Perennial grass populations propagate vegetatively via the belowground bud bank. Climate, photosynthetic pathway, and growth form impact bud production, longevity, and dormancy; leading to alterations… (more)

Ott, Jacqueline P

2014-01-01

36

Transcriptome analysis identifies novel responses and potential regulatory genes involved in seasonal dormancy transitions of leafy spurge (Euphorbia esula L.)  

Microsoft Academic Search

BACKGROUND: Dormancy of buds is a critical developmental process that allows perennial plants to survive extreme seasonal variations in climate. Dormancy transitions in underground crown buds of the model herbaceous perennial weed leafy spurge were investigated using a 23 K element cDNA microarray. These data represent the first large-scale transcriptome analysis of dormancy in underground buds of an herbaceous perennial

David P Horvath; Wun S Chao; Jeffrey C Suttle; Jyothi Thimmapuram; James V Anderson

2008-01-01

37

Stamen development and winter dormancy in apricot (Prunus armeniaca)  

PubMed Central

Background and Aims In temperate woody perennials, flower bud development is halted during the winter, when the buds enter dormancy. This dormant period is a prerequisite for adequate flowering, is genetically regulated, and plays a clear role in possibly adapting species and cultivars to climatic areas. However, information on the biological events underpinning dormancy is lacking. Stamen development, with clear differentiated stages, appears as a good framework to put dormancy in a developmental context. Here, stamen developmental changes are characterized in apricot (Prunus armeniaca) and are related to dormancy. Methods Stamen development was characterized cytochemically from the end of August to March, over 4 years. Developmental changes were related to dormancy, using the existing empirical information on chilling requirements. Key Results Stamen development continued during the autumn, and the flower buds entered dormancy with a fully developed sporogenous tissue. Although no anatomical changes were observed during dormancy, breaking of dormancy occurred following a clear sequence of events. Starch accumulated in particular places, pre-empting further development in those areas. Vascular bundles developed and pollen mother cells underwent meiosis followed by microspore development. Conclusions Dormancy appears to mark a boundary between the development of the sporogenous tissue and the occurrence of meiosis for further microspore development. Breaking of dormancy occurs following a clear sequence of events, providing a developmental context in which to study winter dormancy and to evaluate differences in chilling requirements among genotypes. PMID:21474504

Julian, C.; Rodrigo, J.; Herrero, M.

2011-01-01

38

Phylogenetic analysis and molecular evolution of the dormancy associated MADS-box genes from peach  

Microsoft Academic Search

BACKGROUND: Dormancy associated MADS-box (DAM) genes are candidates for the regulation of growth cessation and terminal bud formation in peach. These genes are not expressed in the peach mutant evergrowing, which fails to cease growth and enter dormancy under dormancy-inducing conditions. We analyzed the phylogenetic relationships among and the rates and patterns of molecular evolution within DAM genes in the

Sergio Jiménez; Amy L Lawton-Rauh; Gregory L Reighard; Albert G Abbott; Douglas G Bielenberg

2009-01-01

39

Changes in the activities of catalase, peroxidase, and polyphenol oxidase in apple buds during bud break induced by thidiazuron  

Microsoft Academic Search

The breaking of dormancy in apple buds (Malus domestica Borkh cv. York Imperial) by thidiazuron (N-phenyl-N?-1,2,3,-thidiazol-5-ylurea) was investigated in relation to catalase, peroxidase, and polyphenol oxidase activities and their\\u000a isoenzyme patterns. The activity and number of isoenzymic components of catalase increased progressively during bud break,\\u000a then decreased after buds started to grow. Peroxidase activity was highest during dormancy and declined

Shiow Y. Wang; Hong J. Jiao; Miklos Faust

1991-01-01

40

Seasonal variation of hydrophilic, hydrophobic, and charged amino acids in developing apple flower buds  

Microsoft Academic Search

An increase in polar amino acids especially in hydrophilic and charged amino acids and a decrease in hydrophobic amino acids were observed in developing apple flower buds from July to November (beginning of dormancy). This suggests that polar amino acids may play a role in dormancy of apple flower buds similar to that of other polar substances. A 2nd?degree polynomial

S. Khanizadeh; D. Buszard; C. G. Zarkadas

1994-01-01

41

Transcriptome variation along bud development in grapevine (Vitis vinifera L.)  

PubMed Central

Background Vegetative buds provide plants in temperate environments the possibility for growth and reproduction when environmental conditions are favorable. In grapevine, crucial developmental events take place within buds during two growing seasons in consecutive years. The first season, the shoot apical meristem within the bud differentiates all the basic elements of the shoot including flowering transition in lateral primordia and development of inflorescence primordia. These events practically end with bud dormancy. The second season, buds resume shoot growth associated to flower formation and development. Gene expression has been previously monitored at specific stages of bud development but has never been followed along the two growing seasons. Results Gene expression changes were analyzed along the bud annual cycle at eight different time points. Principal Components Analysis (PCA) revealed that the main factors explaining the global gene expression differences were the processes of bud dormancy and active growth as well as stress responses. Accordingly, non dormant buds showed an enrichment in functional categories typical of actively proliferating and growing cells together with the over abundance of transcripts belonging to stress response pathways. Differential expression analyses performed between consecutive time points indicated that major transcriptional changes were associated to para/endodormancy, endo/ecodormancy and ecodormancy/bud break transitions. Transcripts encoding key regulators of reproductive development were grouped in three major expression clusters corresponding to: (i) transcripts associated to flowering induction, (ii) transcripts associated to flower meristem specification and initiation and (iii) transcripts putatively involved in dormancy. Within this cluster, a MADS-box gene (VvFLC2) and other transcripts with similar expression patterns could participate in dormancy regulation. Conclusions This work provides a global view of major transcriptional changes taking place along bud development in grapevine, highlighting those molecular and biological functions involved in the main events of bud development. As reported in other woody species, the results suggest that genes regulating flowering could also be involved in dormancy regulatory pathways in grapevine. PMID:23035802

2012-01-01

42

Photoperiod and temperature responses of bud swelling and bud burst in four temperate forest tree species.  

PubMed

Spring phenology of temperate forest trees is optimized to maximize the length of the growing season while minimizing the risk of freezing damage. The release from winter dormancy is environmentally mediated by species-specific responses to temperature and photoperiod. We investigated the response of early spring phenology to temperature and photoperiod at different stages of dormancy release in cuttings from four temperate tree species in controlled environments. By tracking bud development, we were able to identify the onset of bud swelling and bud growth in Acer pseudoplatanus L., Fagus sylvatica L., Quercus petraea (Mattuschka) Liebl. and Picea abies (L.) H. Karst. At a given early stage of dormancy release, the onset and duration of the bud swelling prior to bud burst are driven by concurrent temperature and photoperiod, while the maximum growth rate is temperature dependent only, except for Fagus, where long photoperiods also increased bud growth rates. Similarly, the later bud burst was controlled by temperature and photoperiod (in the photoperiod sensitive species Fagus, Quercus and Picea). We conclude that photoperiod is involved in the release of dormancy during the ecodormancy phase and may influence bud burst in trees that have experienced sufficient chilling. This study explored and documented the early bud swelling period that precedes and defines later phenological stages such as canopy greening in conventional phenological works. It is the early bud growth resumption that needs to be understood in order to arrive at a causal interpretation and modelling of tree phenology at a large scale. Classic spring phenology events mark visible endpoints of a cascade of processes as evidenced here. PMID:24713858

Basler, David; Körner, Christian

2014-04-01

43

The resemblance and disparity of gene expression in dormant and non-dormant seeds and crown buds of leafy spurge (Euphorbia esula)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Overlaps in transcriptome profiles between different phases of bud and seed dormancy have not been determined. Thus, we compared various phases of dormancy between seeds and buds to identify common genes and molecular processes. Cluster analysis of expression profiles for 201 selected genes indicate...

44

Changes in Cytokinins before and during Early Flower Bud Differentiation in Lychee (Litchi chinensis Sonn.) 1  

PubMed Central

Lychee (Litchi chinensis) has been analyzed for cytokinins in buds before and after flower bud differentiation, using reversephase high performance liquid chromatography in combination with Amaranthus bioassay and gas chromatography-mass spectrometry-selected ion monitoring. Four cytokinins, zeatin, zeatin riboside, N6-(?2-isopentenyl)adenine, and N6-(?6-isopentenyl) adenine riboside, were detected in buds. There was an increase of cytokinin activity in the buds during flower bud differentiation. In dormant buds, the endogenous cytokinin content was low, and the buds did not respond to exogenous cytokinin application. Application of kinetin promotes flower bud differentiation significantly after bud dormancy. These results are interpreted as an indication that the increase in endogenous cytokinin levels during flower bud differentiation may be correlative rather than the cause of flower bud initiation. PMID:16668321

Chen, Wen-Shaw

1991-01-01

45

Seed dormancy and germination  

Microsoft Academic Search

Seed dormancy and germination are complex adaptive traits of higher plants that are influenced by a large number of genes and environmental factors. Studies of genetics and physiology have shown the important roles of the plant hormones abscisic acid and gibberellin in the regulation of dormancy and germination. More recently, the use of quantitative genetics and mutant approaches has allowed

Maarten Koornneef; Leónie Bentsink; Henk Hilhorst

2002-01-01

46

Indoleacetic acid concentration and metabolism changes during bud development in tubers of two potato (Solanum tuberosum) cultivars.  

PubMed

Plant growth regulators are involved in the control of potato (Solanum tuberosum) tuber dormancy. Evidence concerning the role of IAA is controversial; we therefore investigated its role by analyzing two cultivars with varying lengths of dormancy. We examined the time course of free and conjugated IAA in tuber tissue isolates from the final stages of tuber growth to the end of dormancy, the distribution of free IAA in tuber tissues by in situ analysis, and the biosynthesis of the hormone by feeding experiments. The time course of free IAA showed marked differences between the examined cultivars, although the concentration of the auxin generally was the highest at the early stages of tuber dormancy. Immunodetection showed a similar pattern of IAA distribution in both genotypes: in dormant buds from freshly harvested tubers, the free hormone accumulated mostly in apical meristem, leaf and lateral bud primordia, and differentiating vascular tissues underlying the apical meristem, while at the end of the storage period only axillary bud primordia from growing buds displayed appreciable auxin levels. Feeding experiments indicated that changes in IAA biosynthesis rate were a major cause of auxin variation in buds. In both cultivars, dormancy apparently ceased when free IAA fell below a threshold value. Despite this, our data led us to conclude that IAA would not be directly responsible for inhibiting sprouting. Instead, auxin might shorten dormancy, in a cultivar-dependent manner, by enhancing early developmental processes in buds, ultimately leading to dormancy termination. PMID:19269711

Sorce, Carlo; Lombardi, Lara; Giorgetti, Lucia; Parisi, Bruno; Ranalli, Paolo; Lorenzi, Roberto

2009-07-01

47

Potato tuber cytokinin oxidase/dehydrogenase genes: biochemical properties, activity, and expression during tuber dormancy progression.  

PubMed

The enzymatic and biochemical properties of the proteins encoded by five potato cytokinin oxidase/dehydrogenase (CKX)-like genes functionally expressed in yeast and the effects of tuber dormancy progression on StCKX expression and cytokinin metabolism were examined in lateral buds isolated from field-grown tubers. All five putative StCKX genes encoded proteins with in vitro CKX activity. All five enzymes were maximally active at neutral to slightly alkaline pH with 2,6-dichloro-indophenol as the electron acceptor. In silico analyses indicated that four proteins were likely secreted. Substrate dependence of two of the most active enzymes varied; one exhibiting greater activity with isopentenyl-type cytokinins while the other was maximally active with cis-zeatin as a substrate. [(3)H]-isopentenyl-adenosine was readily metabolized by excised tuber buds to adenine/adenosine demonstrating that CKX was active in planta. There was no change in apparent in planta CKX activity during either natural or chemically forced dormancy progression. Similarly although expression of individual StCKX genes varied modestly during tuber dormancy, there was no clear correlation between StCKX gene expression and tuber dormancy status. Thus although CKX gene expression and enzyme activity are present in potato tuber buds throughout dormancy, they do not appear to play a significant role in the regulation of cytokinin content during tuber dormancy progression. PMID:24594397

Suttle, Jeffrey C; Huckle, Linda L; Lu, Shunwen; Knauber, Donna C

2014-03-15

48

Transcript profiling in Vitis riparia during chilling requirement fulfillment reveals coordination of gene expression patterns with optimized bud break  

Microsoft Academic Search

Endodormant grapevine buds require a period of chilling before they break and begin to grow. Custom Vitis bud cDNA microarrays (9,216 features) were used to examine gene expression patterns in overwintering Vitis riparia buds during 2,000 h of 4°C chilling. Three-node cuttings collected concurrently with buds were monitored to determine dormancy\\u000a status. Chilling requirement was fulfilled after 1,500 h of chilling; however,

Kathy Mathiason; Dong He; Jérôme Grimplet; J. Venkateswari; David W. Galbraith; Etti; Anne Fennell

2009-01-01

49

Phases of Dormancy in Yam Tubers (Dioscorea rotundata)  

PubMed Central

• Background and Aims The control of dormancy in yam (Disocorea spp.) tubers is poorly understood and attempts to shorten the long dormant period (i.e. cause tubers to sprout or germinate much earlier) have been unsuccessful. The aim of this study was to identify and define the phases of dormancy in Dioscorea rotundata tubers, and to produce a framework within which dormancy can be more effectively studied. • Methods Plants of ‘TDr 131’ derived from tissue culture were grown in a glasshouse simulating temperature and photoperiod at Ibadan (7°N), Nigeria to produce tubers. Tubers were sampled on four occasions: 30?d before shoot senescence (149 days after planting, DAP), at shoot senescence (179 DAP), and twice during storage at a constant 25?°C (269 and 326 DAP). The development of the apical shoot bud was described from tissue sections. In addition, the responsiveness of shoot apical bud development to plant growth regulators (gibberellic acid, 2-chloroethanol and thiourea) applied to excised tuber sections was also examined 6 and 12?d after treatment. • Key Results and Conclusions Three phases of tuber dormancy are proposed: Phase I, from tuber initiation to the appearance of the tuber germinating meristem; Phase II, from the tuber germinating meristem to initiation of foliar primordium; and Phase III, from foliar primordium to appearance of the shoot bud on the surface of the tuber. Phase I is the longest phase (approx. 220?d in ‘TDr 131’), is not affected by PGRs and is proposed to be an endo-dormant phase. Phases II and III are shorter (<70?d in total), are influenced by PGRs and environmental conditions, and are therefore endo-/eco-dormant phases. To manipulate dormancy to allow off-season planting and more than one generation per year requires that the duration of Phase I is shortened. PMID:16446288

ILE, E. I.; CRAUFURD, P. Q.; BATTEY, N. H.; ASIEDU, R.

2006-01-01

50

Seed dormancy in alpine species.  

PubMed

In alpine species the classification of the various mechanisms underlying seed dormancy has been rather questionable and controversial. Thus, we investigated 28 alpine species to evaluate the prevailing types of dormancy. Embryo type and water impermeability of seed coats gave an indication of the potential seed dormancy class. To ascertain the actual dormancy class and level, we performed germination experiments comparing the behavior of seeds without storage, after cold-dry storage, after cold-wet storage, and scarification. We also tested the light requirement for germination in some species. Germination behavior was characterized using the final germination percentage and the mean germination time. Considering the effects of the pretreatments, a refined classification of the prevailing dormancy types was constructed based on the results of our pretreatments. Only two out of the 28 species that we evaluated had predominantly non-dormant seeds. Physiological dormancy was prevalent in 20 species, with deep physiological dormancy being the most abundant, followed by non-deep and intermediate physiological dormancy. Seeds of four species with underdeveloped embryos were assigned to the morphophysiologial dormancy class. An impermeable seed coat was identified in two species, with no additional physiological germination block. We defined these species as having physical dormancy. Light promoted the germination of seeds without storage in all but one species with physiological dormancy. In species with physical dormancy, light responses were of minor importance. We discuss our new classification in the context of former germination studies and draw implications for the timing of germination in the field. PMID:24415831

Schwienbacher, Erich; Navarro-Cano, Jose Antonio; Neuner, Gilbert; Erschbamer, Brigitta

2011-10-01

51

Dormant buds  

Technology Transfer Automated Retrieval System (TEKTRAN)

Dormant vegetative buds from diverse species can be preserved using cryopreservation. Sakai (1960) provided one of the first studies showing that winter twigs of poplar (Populus sieboldi) and willow (Salix koriyanagi) could survive low temperatures if slowly cooled prior to immersion in liquid nitr...

52

Release of apical dominance in potato tuber is accompanied by programmed cell death in the apical bud meristem.  

PubMed

Potato (Solanum tuberosum) tuber, a swollen underground stem, is used as a model system for the study of dormancy release and sprouting. Natural dormancy release, at room temperature, is initiated by tuber apical bud meristem (TAB-meristem) sprouting characterized by apical dominance (AD). Dormancy is shortened by treatments such as bromoethane (BE), which mimics the phenotype of dormancy release in cold storage by inducing early sprouting of several buds simultaneously. We studied the mechanisms governing TAB-meristem dominance release. TAB-meristem decapitation resulted in the development of increasing numbers of axillary buds with time in storage, suggesting the need for autonomous dormancy release of each bud prior to control by the apical bud. Hallmarks of programmed cell death (PCD) were identified in the TAB-meristems during normal growth, and these were more extensive when AD was lost following either extended cold storage or BE treatment. Hallmarks included DNA fragmentation, induced gene expression of vacuolar processing enzyme1 (VPE1), and elevated VPE activity. VPE1 protein was semipurified from BE-treated apical buds, and its endogenous activity was fully inhibited by a cysteinyl aspartate-specific protease-1-specific inhibitor N-Acetyl-Tyr-Val-Ala-Asp-CHO (Ac-YVAD-CHO). Transmission electron microscopy further revealed PCD-related structural alterations in the TAB-meristem of BE-treated tubers: a knob-like body in the vacuole, development of cytoplasmic vesicles, and budding-like nuclear segmentations. Treatment of tubers with BE and then VPE inhibitor induced faster growth and recovered AD in detached and nondetached apical buds, respectively. We hypothesize that PCD occurrence is associated with the weakening of tuber AD, allowing early sprouting of mature lateral buds. PMID:22362870

Teper-Bamnolker, Paula; Buskila, Yossi; Lopesco, Yael; Ben-Dor, Shifra; Saad, Inbal; Holdengreber, Vered; Belausov, Eduard; Zemach, Hanita; Ori, Naomi; Lers, Amnon; Eshel, Dani

2012-04-01

53

Early wound reactions of Japanese maple during winter dormancy: the effect of two contrasting temperature regimes  

PubMed Central

During winter dormancy, temperate trees are capable of only a restricted response to wounding. Depending on the ambient temperature during winter dormancy, wounded trees may start compartmentalization, e.g. by producing inhibitory compounds, but it is thought that processes involving cell proliferation, such as the formation of callus and wound xylem, are delayed until the next growing season. We investigated the effect of two contrasting temperature regimes on early reactions of Acer palmatum trees to wounding during winter bud dormancy. Stems of A. palmatum trees were wounded and stored under an ambient temperature of 4 or 15 °C for 3 weeks during winter bud dormancy. We then studied wound reactions in the living bark, cambial region and xylem. In the 4 °C treatment, wound reactions were virtually absent. In the 15 °C treatment, however, trees reacted to wounding by dieback of the cortex and phloem and by the formation of ligno-suberized layers. In the cambial zone, cambial dieback occurred and callus tissue and wound xylem were formed locally, close to the wound margins. In the xylem, compartmentalization took place by deposition of inhibitory compounds in fibre cells and vessel elements. We conclude that temperature is an important factor in wound reactions during winter dormancy, and may even induce proliferation of callus and wound xylem within a 3-week period. It therefore seems likely that trees that have been wounded during dormancy in areas with mild or warm winters might cope better with wounding, as unlike trees in cold environments, they may compartmentalize wounds even during winter dormancy. PMID:25275087

Copini, Paul; den Ouden, Jan; Decuyper, Mathieu; Mohren, Godefridus M. J.; Loomans, Antoon J. M.; Sass-Klaassen, Ute

2014-01-01

54

Effect of alternating day and night temperature on short day-induced bud set and subsequent bud burst in long days in Norway spruce  

PubMed Central

Young seedlings of the conifer Norway spruce exhibit short day (SD)-induced cessation of apical growth and bud set. Although different, constant temperatures under SD are known to modulate timing of bud set and depth of dormancy with development of deeper dormancy under higher compared to lower temperature, systematic studies of effects of alternating day (DT) and night temperatures (NT) are limited. To shed light on this, seedlings of different provenances of Norway spruce were exposed to a wide range of DT-NT combinations during bud development, followed by transfer to forcing conditions of long days (LD) and 18°C, directly or after different periods of chilling. Although no specific effect of alternating DT/NT was found, the results demonstrate that the effects of DT under SD on bud set and subsequent bud break are significantly modified by NT in a complex way. The effects on bud break persisted after chilling. Since time to bud set correlated with the daily mean temperature under SD at DTs of 18 and 21°C, but not a DT of 15°C, time to bud set apparently also depend on the specific DT, implying that the effect of NT depends on the actual DT. Although higher temperature under SD generally results in later bud break after transfer to forcing conditions, the fastest bud flush was observed at intermediate NTs. This might be due to a bud break-hastening chilling effect of intermediate compared to higher temperatures, and delayed bud development to a stage where bud burst can occur, under lower temperatures. Also, time to bud burst in un-chilled seedlings decreased with increasing SD-duration, suggesting that bud development must reach a certain stage before the processes leading to bud burst are initiated. The present results also indicate that low temperature during bud development had a larger effect on the most southern compared to the most northern provenance studied. Decreasing time to bud burst was observed with increasing northern latitude of origin in un-chilled as well as chilled plants. In conclusion, being a highly temperature-dependent process, bud development is strongly delayed by low temperature, and the effects of DT is significantly modified by NT in a complex manner. PMID:25538722

Olsen, Jorunn E.; Lee, YeonKyeong; Junttila, Olavi

2014-01-01

55

Effect of alternating day and night temperature on short day-induced bud set and subsequent bud burst in long days in Norway spruce.  

PubMed

Young seedlings of the conifer Norway spruce exhibit short day (SD)-induced cessation of apical growth and bud set. Although different, constant temperatures under SD are known to modulate timing of bud set and depth of dormancy with development of deeper dormancy under higher compared to lower temperature, systematic studies of effects of alternating day (DT) and night temperatures (NT) are limited. To shed light on this, seedlings of different provenances of Norway spruce were exposed to a wide range of DT-NT combinations during bud development, followed by transfer to forcing conditions of long days (LD) and 18°C, directly or after different periods of chilling. Although no specific effect of alternating DT/NT was found, the results demonstrate that the effects of DT under SD on bud set and subsequent bud break are significantly modified by NT in a complex way. The effects on bud break persisted after chilling. Since time to bud set correlated with the daily mean temperature under SD at DTs of 18 and 21°C, but not a DT of 15°C, time to bud set apparently also depend on the specific DT, implying that the effect of NT depends on the actual DT. Although higher temperature under SD generally results in later bud break after transfer to forcing conditions, the fastest bud flush was observed at intermediate NTs. This might be due to a bud break-hastening chilling effect of intermediate compared to higher temperatures, and delayed bud development to a stage where bud burst can occur, under lower temperatures. Also, time to bud burst in un-chilled seedlings decreased with increasing SD-duration, suggesting that bud development must reach a certain stage before the processes leading to bud burst are initiated. The present results also indicate that low temperature during bud development had a larger effect on the most southern compared to the most northern provenance studied. Decreasing time to bud burst was observed with increasing northern latitude of origin in un-chilled as well as chilled plants. In conclusion, being a highly temperature-dependent process, bud development is strongly delayed by low temperature, and the effects of DT is significantly modified by NT in a complex manner. PMID:25538722

Olsen, Jorunn E; Lee, YeonKyeong; Junttila, Olavi

2014-01-01

56

Effect of chilling on calorimetric responses of dormant vegetative apple buds  

Microsoft Academic Search

Chilling exposure is important in apple buds to overcome dormancy. The objective of this work was to determine the effect of different chilling treatments on apple bud calorimetric responses. One-year-old Golden Delicious trees were kept in a controlled temperature chamber at 4°C for up to 1600h. At 200h intervals, five trees were transferred to forcing conditions at 25°C. Isothermal calorimetry

A. A Gardea; E Carvajal-Millán; J. A Orozco; V. M Guerrero; J Llamas

2000-01-01

57

Localization, characterization and candidate gene discovery for genes controlling dormancy, chilling requirement, bloom time, and heat requirement in Prunus species.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Perennial fruiting trees require sustained exposure to low, near freezing, temperatures before vigorous floral and vegetative bud break is possible after the resumption of warm temperatures in the spring. The depth of dormancy, duration of chilling required (the chilling requirement, CR) blooming da...

58

The Normalcy of Dormancy  

PubMed Central

All microorganisms are exposed to periodic stresses that inhibit growth. Many bacteria and fungi weather these periods by entering a hardy, non-replicating state, often termed quiescence or dormancy. When this occurs during an infection, the resulting slowly-growing pathogen is able to tolerate both immune insults and prolonged antibiotic exposure. While the stresses encountered in a free-living environment may differ from those imposed by host immunity, these growth-limiting conditions impose common pressures and many of the corresponding microbial responses appear to be universal. In this review, we discuss the common features of these growth-limited states, which suggest new approaches for treating chronic infections such as tuberculosis. PMID:23768489

Rittershaus, Emily S. C.; Baek, Seung-hun; Sassetti, Christopher M.

2013-01-01

59

Effects of Oxygen and Respiratory Inhibitors on Induction and Release of Dormancy in Aerial Tubers of Begonia evansiana  

PubMed Central

Effects of O2 and some respiratory inhibitors on the induction and release of bud dormancy were examined with the aerial tubers of different ages of Begonia evansiana Andr. Oxygen was needed not only for tuber sprouting but also during the chilling process at 2 to 5 C to break tuber dormancy. If the mature tubers were exposed to blue light during the chilling period, their dormancy was strikingly released even by the chilling given under an O2 concentration as low as 3%. Blue light pretreatment promoted photo-sprouting of immature tubers only when given under lower O2 concentrations. On the other hand, red light became effective in inducing dormancy in the immature tubers and in prolonging dormancy in the mature tubers as O2 tension was increased. This was also the case with the induction of dormancy in the immature tubers by exposing them to a lower temperature (17 C) in the dark. The development of dormancy was suppressed by 2,4-dinitrophenol, p-nitrophenol, and sodium azide. PMID:16658360

Esashi, Y.; Nagao, M.

1973-01-01

60

Release of Apical Dominance in Potato Tuber Is Accompanied by Programmed Cell Death in the Apical Bud Meristem[C][W  

PubMed Central

Potato (Solanum tuberosum) tuber, a swollen underground stem, is used as a model system for the study of dormancy release and sprouting. Natural dormancy release, at room temperature, is initiated by tuber apical bud meristem (TAB-meristem) sprouting characterized by apical dominance (AD). Dormancy is shortened by treatments such as bromoethane (BE), which mimics the phenotype of dormancy release in cold storage by inducing early sprouting of several buds simultaneously. We studied the mechanisms governing TAB-meristem dominance release. TAB-meristem decapitation resulted in the development of increasing numbers of axillary buds with time in storage, suggesting the need for autonomous dormancy release of each bud prior to control by the apical bud. Hallmarks of programmed cell death (PCD) were identified in the TAB-meristems during normal growth, and these were more extensive when AD was lost following either extended cold storage or BE treatment. Hallmarks included DNA fragmentation, induced gene expression of vacuolar processing enzyme1 (VPE1), and elevated VPE activity. VPE1 protein was semipurified from BE-treated apical buds, and its endogenous activity was fully inhibited by a cysteinyl aspartate-specific protease-1-specific inhibitor N-Acetyl-Tyr-Val-Ala-Asp-CHO (Ac-YVAD-CHO). Transmission electron microscopy further revealed PCD-related structural alterations in the TAB-meristem of BE-treated tubers: a knob-like body in the vacuole, development of cytoplasmic vesicles, and budding-like nuclear segmentations. Treatment of tubers with BE and then VPE inhibitor induced faster growth and recovered AD in detached and nondetached apical buds, respectively. We hypothesize that PCD occurrence is associated with the weakening of tuber AD, allowing early sprouting of mature lateral buds. PMID:22362870

Teper-Bamnolker, Paula; Buskila, Yossi; Lopesco, Yael; Ben-Dor, Shifra; Saad, Inbal; Holdengreber, Vered; Belausov, Eduard; Zemach, Hanita; Ori, Naomi; Lers, Amnon; Eshel, Dani

2012-01-01

61

Roles of Endoplasmic Reticulum Stress and Unfolded Protein Response Associated Genes in Seed Stratification and Bud Endodormancy during Chilling Accumulation in Prunus persica  

PubMed Central

Dormancy mechanisms in seeds and buds arrest growth until environmental conditions are optimal for development. A genotype-specific period of chilling is usually required to release dormancy, but the underlying molecular mechanisms are still not fully understood. To discover transcriptional pathways associated with dormancy release common to seed stratification and bud endodormancy, we explored the chilling-dependent expression of 11 genes involved in endoplasmic reticulum stress and the unfolded protein response signal pathways. We propose that endoplasmic reticulum stress and the unfolded protein response impact on seed as well as bud germination and development by chilling-dependent mechanisms. The emerging discovery of similarities between seed stratification and bud endodormancy status indicate that these two processes are probably regulated by common endoplasmic reticulum stress and unfolded protein response signalling pathways. Clarification of regulatory pathways common to both seed and bud dormancy may enhance understanding of the mechanisms underlying dormancy and breeding programs may benefit from earlier prediction of chilling requirements for uniform blooming of novel genotypes of deciduous fruit tree species. PMID:24999812

Fu, Xi Ling; Xiao, Wei; Wang, Dong Ling; Chen, Min; Tan, Qiu Ping; Li, Ling; De Chen, Xiu; Gao, Dong Sheng

2014-01-01

62

RNA-Seq-based transcriptome analysis of dormant flower buds of Chinese cherry (Prunus pseudocerasus).  

PubMed

Bud dormancy is a critical biological process allowing Chinese cherry (Prunus pseudocerasus) to survive in winter. Due to the lake of genomic information, molecular mechanisms triggering endodormancy release in flower buds have remained unclear. Hence, we used Illumina RNA-Seq technology to carry out de novo transcriptome assembly and digital gene expression profiling of flower buds. Approximately 47million clean reads were assembled into 50,604 sequences with an average length of 837bp. A total of 37,650 unigene sequences were successfully annotated. 128 pathways were annotated by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and metabolic, biosynthesis of second metabolite and plant hormone signal transduction accounted for higher percentage in flower bud. In critical period of endodormancy release, 1644, significantly differentially expressed genes (DEGs) were identified from expression profile. DEGs related to oxidoreductase activity were especially abundant in Gene Ontology (GO) molecular function category. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis demonstrated that DEGs were involved in various metabolic processes, including phytohormone metabolism. Quantitative real-time PCR (qRT-PCR) analysis indicated that levels of DEGs for abscisic acid and gibberellin biosynthesis decreased while the abundance of DEGs encoding their degradation enzymes increased and GID1 was down-regulated. Concomitant with endodormancy release, MADS-box transcription factors including P. pseudocerasus dormancy-associated MADS-box (PpcDAM), Agamous-like2, and APETALA3-like genes, shown remarkably epigenetic roles. The newly generated transcriptome and gene expression profiling data provide valuable genetic information for revealing transcriptomic variation during bud dormancy in Chinese cherry. The uncovered data should be useful for future studies of bud dormancy in Prunus fruit trees lacking genomic information. PMID:25447903

Zhu, Youyin; Li, Yongqiang; Xin, Dedong; Chen, Wenrong; Shao, Xu; Wang, Yue; Guo, Weidong

2015-01-25

63

Differential floral development and gene expression in grapevines during long and short photoperiods suggests a role for floral genes in dormancy transitioning  

Microsoft Academic Search

Daylength is an important environmental cue for synchronizing growth, flowering, and dormancy with seasonality. As many floral\\u000a development genes are photoperiod regulated, it has been suggested that they could have a regulatory role in bud endodormancy.\\u000a Therefore, the influence of photoperiod was studied on inflorescence primordia differentiation and floral pathway related\\u000a gene expression during the development of overwintering buds in

Lekha Sreekantan; Kathy Mathiason; Jérôme Grimplet; Karen Schlauch; Julie A. Dickerson; Anne Y. Fennell

2010-01-01

64

KNAP2, a class I KN1-like gene is a negative marker of bud growth potential in apple trees (Malus domestica [L.] Borkh.)  

Microsoft Academic Search

The determinism of bud bursting pattern along the 1-year-old shoot was studied at the molecular and morphological levels in the apple tree variety 'Lodi' which shows an acrotonic tendency. At the molecular level, the expression of KNAP2, which belongs to the class I KN1-like gene family, was studied. Measurements were carried out during dormancy (October), breaking dormancy (January) and just

Nicole Brunel; Nathalie Leduc; Pascal Poupard; Philippe Simoneau; Jean-Claude Mauget; Jean-Daniel Viemont

2002-01-01

65

EARLY ENTRANCE COPRODUCTION PLANT  

Microsoft Academic Search

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine

Fred D. Brent; Lalit Shah; Earl Berry; Charles H. Schrader; John Anderson; J. Erwin; Matthew G. Banks; Terry L. Ullman

2004-01-01

66

SUBTRACTIVE CDNA LIBRARIES IDENTIFY DIFFERENTIALLY-EXPRESSED GENES IN DORMANT AND GROWING BUDS OF LEAFY SPURGE (EUPHORBIA ESULA)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two subtracted cDNA libraries (growing and paradormant) were developed to study genes associated with bud dormancy and initiation of shoot growth in leafy spurge. Initial analysis revealed that both libraries contained many redundant clones. To identify unique sequences represented in each library, ...

67

Experiences with dormancy in tardigrades  

Microsoft Academic Search

Tardigrades often colonise extreme habitats, in which they survive using both types of dormancy: quiescence and diapause. To- gether with nematodes and bdelloid rotifers, tardigrades are known to enter quiescence (with several forms of cryptobiosis: anhy- drobiosis, cryobiosis, anoxybiosis, osmobiosis) at any stage of their life cycle, from egg to adult. Entering anhydrobiosis, tardigrades contract their body into a so-called

Roberto BERTOLANI; Roberto GUIDETTI; K. Ingemar JÖNSSON; Tiziana ALTIERO; Deborah BOSCHINI; Lorena REBECCHI

2004-01-01

68

MRI can reveal metabolic changes in lily bulbs in vivo during dormancy release.  

PubMed

The factors influencing dormancy release in lily bulbs strongly affect commercialization success, but the mechanism of dormancy release is still unclear. Magnetic resonance imaging (MRI) can detect changes in morphology and water status in a living plant bulb and aid in investigating release factors. To evaluate whether MRI could be used to detect intra-bulb metabolic changes during the dormant period in Oriental Lilies (Lilium 'Sorbonne'), a series of MRI and sugar concentration measurements were performed weekly on bulbs stored for 11 weeks at 4°C. The image quality of intra-bulb structure obtained using T (1)-weighted imaging was superior to that obtained using T (2)-weighted imaging and had a higher signal-to-noise ratio (0.97 ± 0.01). Magnetization transfer ratio values for the bud and basal plate declined during the first eight weeks of cold storage (P>0.05), and were well correlated with concentration of soluble sugar in the bud (R (2)=0.95) and basal plate (R (2)=0.93). Thus, MRI can serve as a valuable tool for observation and analysis of dynamic morphological and metabolic changes in vivo during dormancy release. This information is potentially useful as a guide in the improvement of horticultural product quality. PMID:23124794

Han, Haojun; Yi, Mingfang

2012-11-01

69

Transcript Profiling of Paoenia ostii during Artificial Chilling Induced Dormancy Release Identifies Activation of GA Pathway and Carbohydrate Metabolism  

PubMed Central

Endo-dormant flower buds must pass through a period of chilling to reinitiate growth and subsequent flowering, which is a major obstacle to the forcing culture of tree peony in winter. Customized cDNA microarray (8×15 K element) was used to investigate gene expression profiling in tree peony ‘Feng Dan Bai’ buds during 24 d chilling treatment at 0–4°C. According to the morphological changes after the whole plants were transferred to green house, endo-dormancy was released after 18 d chilling treatment, and prolonged chilling treatment increased bud break rate. Pearson correlation hierarchical clustering of sample groups was highly consistent with the dormancy transitions revealed by morphological changes. Totally 3,174 significantly differentially-expressed genes (P<0.05) were observed through endo-dormancy release process, of which the number of up-regulated (1,611) and that of down-regulated (1,563) was almost the same. Functional annotation of differentially-expressed genes revealed that cellular process, metabolic process, response to stimulus, regulation of biological process and development process were well-represented. Hierarchical clustering indicated that activation of genes involved in carbohydrate metabolism (Glycolysis, Citrate cycle and Pentose phosphate pathway), energy metabolism and cell growth. Based on the results of GO analysis, totally 51 probes presented in the microarray were associated with GA response and GA signaling pathway, and 22 of them were differently expressed. The expression profiles also revealed that the genes of GA biosynthesis, signaling and response involved in endo-dormancy release. We hypothesized that activation of GA pathway played a central role in the regulation of dormancy release in tree peony. PMID:23405132

Liu, Chunying; Zhang, Yang; Zheng, Guosheng

2013-01-01

70

Summer Dormancy in Perennial Temperate Grasses  

PubMed Central

• Background and Aims Dormancy has been extensively studied in plants which experience severe winter conditions but much less so in perennial herbaceous plants that must survive summer drought. This paper reviews the current knowledge on summer dormancy in both native and cultivated perennial temperate grasses originating from the Mediterranean Basin, and presents a unified terminology to describe this trait. • Scope Under severe drought, it is difficult to separate the responses by which plants avoid and tolerate dehydration from those associated with the expression of summer dormancy. Consequently, this type of endogenous (endo-) dormancy can be tested only in plants that are not subjected to moisture deficit. Summer dormancy can be defined by four criteria, one of which is considered optional: (1) reduction or cessation of leaf production and expansion; (2) senescence of mature foliage; (3) dehydration of surviving organs; and (4, optional) formation of resting organs. The proposed terminology recognizes two levels of summer dormancy: (a) complete dormancy, when cessation of growth is associated with full senescence of foliage and induced dehydration of leaf bases; and (b) incomplete dormancy, when leaf growth is partially inhibited and is associated with moderate levels of foliage senescence. Summer dormancy is expressed under increasing photoperiod and temperature. It is under hormonal control and usually associated with flowering and a reduction in metabolic activity in meristematic tissues. Dehydration tolerance and dormancy are independent phenomena and differ from the adaptations of resurrection plants. • Conclusions Summer dormancy has been correlated with superior survival after severe and repeated summer drought in a large range of perennial grasses. In the face of increasing aridity, this trait could be used in the development of cultivars that are able to meet agronomic and environmental goals. It is therefore important to have a better understanding of the genetic and environmental control of summer dormancy. PMID:17028299

VOLAIRE, FLORENCE; NORTON, MARK

2006-01-01

71

Seed dormancy and ABA signaling  

PubMed Central

The seed is an important organ in higher plants, it is an important organ for plant survival and species dispersion. The transition between seed dormancy and germination represents a critical stage in the plant life cycle and it is an important ecological and commercial trait. A dynamic balance of synthesis and catabolism of two antagonistic hormones, abscisic acid (ABA) and giberellins (GAs), controls the equilibrium between seed dormancy and germination. Embryonic ABA plays a central role in induction and maintenance of seed dormancy and also inhibits the transition from embryonic to germination growth. Therefore, the ABA metabolism must be highly regulated at both temporal and spatial levels during phase of dessication tolerance. On the other hand, the ABA levels do not depend exclusively on the seeds because sometimes it becomes a strong sink and imports it from the roots and rhizosphere through the xylem and/or phloem. These events are discussed in depth here. Likewise, the role of some recently characterized genes belonging to seeds of woody species and related to ABA signaling are also included. Finally, although four possible ABA receptors have been reported, not much is known about how they mediate ABA signaling transduction. However, new publications seem to show that almost all these receptors lack several properties to consider them as such. PMID:19875942

del Carmen Rodríguez-Gacio, María; Matilla-Vázquez, Miguel A

2009-01-01

72

Latitudinal variation in sensitivity of flower bud formation to high temperature in Japanese Taraxacum officinale.  

PubMed

Control of flowering time plays a key role in the successful range expansion of plants. Taraxacum officinale has expanded throughout Japan during the 110 years after it was introduced into a cool temperate region. The present study tested a hypothesis that there is a genetic difference in the bud formation time in relation to temperature along latitudinal gradient of T. officinale populations. In Experiment 1, plants from three populations at different latitudes (26, 36, and 43°N) were grown at three temperatures. Time to flower bud appearance did not significantly differ among the three populations when plants were grown at 14 °C, whereas it increased with increasing latitude when grown at 19 and 24 °C. Rosette diameter was not different among the populations, indicating that the variation in bud formation time reflected a difference in genetic control rather than size variation. The latitudinal variation in bud appearance time was confirmed by Experiment 2 in which plants from 17 population were used. In Experiment 3, the size of plants that exhibited late-flowering was studied to test a hypothesis that the variation in flowering time reflects dormancy of vegetative growth, but the late-flowering plants were found to continue growth, indicating that vegetative dormancy was not the cause of the variation. The results clearly indicate that the degree of suppression of flower bud formation at high temperature decreases with latitude from north to south, which is under genetic control. PMID:24585133

Yoshie, Fumio

2014-05-01

73

Cold storage to overcome dormancy affects the carbohydrate status and photosynthetic capacity of Rhododendron simsii.  

PubMed

Global warming leads to increasing irregular and unexpected warm spells during autumn, and therefore natural chilling requirements to break dormancy are at risk. Controlled cold treatment can provide an answer to this problem. Nevertheless, artificial cold treatment will have consequences for carbon reserves and photosynthesis. In this paper, the effect of dark cold storage at 7 °C to break flower bud dormancy in the evergreen Rhododendron simsii was quantified. Carbohydrate and starch content in leaves and flower buds of an early ('Nordlicht'), semi-early ('M. Marie') and late ('Mw. G. Kint') flowering cultivar showed that carbon loss due to respiration was lowest in 'M. Marie', while 'Mw. G. Kint' was completely depleted of starch reserves at the end of cold treatment. Gene isolation resulted in a candidate gene for sucrose synthase (SUS) RsSus, which appears to be homologous to AtSus3 and had a clear increase in expression in leaves during cold treatment. Photosynthesis measurements on 'Nordlicht' and the late-flowering cultivar 'Thesla' showed that during cold treatment, dark respiration decreased 58% and 63%, respectively. Immediately after cold treatment, dark respiration increased and stabilised after 3 days. The light compensation point followed the same trend as dark respiration. Quantum efficiency showed no significant changes during the first days after cold treatment, but was significantly higher than in plants with dormant flower buds at the start of cold treatment. In conclusion, photosynthesis stabilised 3 days after cold treatment and was improved compared to the level before cold treatment. PMID:24854016

Christiaens, A; De Keyser, E; Lootens, P; Pauwels, E; Roldán-Ruiz, I; De Riek, J; Gobin, B; Van Labeke, M-C

2015-01-01

74

RNAi in Budding Yeast  

E-print Network

RNA interference (RNAi), a gene-silencing pathway triggered by double-stranded RNA, is conserved in diverse eukaryotic species but has been lost in the model budding yeast Saccharomyces cerevisiae. Here, we show that RNAi ...

Drinnenberg, Ines A.

75

QTL analysis of potato tuber dormancy.  

PubMed

The potential loss of chemical sprout inhibitors because of public concern over the use of pesticides underscores the desirability of breeding for long dormancy of potato (Solanum tuberosum L.) tubers. Quantitative trait locus (QTL) analyses were performed in reciprocal backcrosses between S. tuberosum and S. berthaultii toward defining the complexity of dormancy. S. berthaultii is a wild Bolivian species characterized by a short-day requirement for tuberization, long tuber dormancy, and resistance to several insect pests. RFLP alleles segregating from the recurrent parents as well as from the interspecific hybrid were monitored in two segregating progenies. We detected QTLs on nine chromosomes that affected tuber dormancy, either alone or through epistatic interactions. Alleles from the wild parent promoted dormancy, with the largest effect at a QTL on chromosome 2. Long dormancy appeared to be recessive in the backcross to S. berthaultii (BCB). In BCB the additive effects of dormancy QTLs accounted for 48% of the measured phenotypic variance, and adding epistatic effects to the model explained only 4% more. In contrast, additive effects explained only 16% of the variance in the backcross to S. tuberosum (BCT), and an additional 24% was explained by the inclusion of epistatic effects. In BCB variation at all QTLs detected was associated with RFLP alleles segregating from the hybrid parent; in BCT all QTLs except for two found through epistasis were detected through RFLP alleles segregating from the recurrent parent. At least three dormancy QTLs mapped to markers previously found to be associated with tuberization in these crosses. PMID:24162286

van den Berg, J H; Ewing, E E; Plaisted, R L; McMurry, S; Bonierbale, M W

1996-08-01

76

Development of dormancy in different lily genotypes regenerated in vitro  

Microsoft Academic Search

Dormancy development in four Lilium genotypes,L. speciosum, Star Gazer, C. King and Snow Queenregenerated in vitro was compared. Major factorsinfluencing dormancy development were the same for different genotypes andespecially L. speciosum and Star Gazer, that are closelyrelated, reacted similarly. Temperature was the main factor in dormancyinduction and breaking. The range of temperatures that induced dormancy and thelevel of dormancy that

M. M. Langens-Gerrits; S. Nashimoto; A. F. Croes; G. J. De Klerk

2001-01-01

77

Multiple risk reduction mechanisms: can dormancy substitute for dispersal?  

Microsoft Academic Search

In a spatiotemporally variable environment, plants use seed dispersal and dormancy to reduce risk. Intuition suggests that dormancy should be able to substitute for dispersal, so that dormancy will reduce the optimal mean dispersal distance, and previous theoretical studies using temporally uncorrelated environments have found this to be true. I show that in the presence of positive temporal correlations, dormancy

Robin E. Snyder

2006-01-01

78

Mycobacterium tuberculosis: Success through dormancy  

PubMed Central

Tuberculosis (TB) remains a major health threat, killing near to 2 million individuals around this globe, annually. The sole vaccine developed almost a century ago, provides limited protection only during childhood. After decades without the introduction of new antibiotics, several candidates are currently undergoing clinical investigation. Curing TB requires prolonged combination chemotherapy with several drugs. Moreover, monitoring the success of therapy is questionable due to the lack of reliable biomarkers. To substantially improve the situation, a detailed understanding of the crosstalk between human host and the pathogen Mycobacterium tuberculosis (Mtb) is vital. Principally, Mtb’s enormous success is based on three capacities: First, reprogramming of macrophages after primary infection/phagocytosis in order to prevent its own destruction; second, initiating the formation of well-organized granulomas, comprising different immune cells to create a confined environment for the host–pathogen standoff; third, the capability to shut down its own central metabolism, terminate replication and thereby transit into a stage of dormancy rendering itself extremely resistant to host defense and drug treatment. Here we review the molecular mechanisms underlying these processes, draw conclusions in a working model of mycobacterial dormancy and highlight gaps in our understanding to be addressed in future research. PMID:22320122

Gengenbacher, Martin; Kaufmann, Stefan H. E.

2012-01-01

79

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan for implementation in Phase II; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation.

Mushtaq Ahmed; John H. Anderson; Earl R. Berry; Fred Brent; Ming He; Jimmy O. Ong; Mike K. Porter; Randy Roberts; Charles H. Schrader; Lalit S. Shah; Kenneth A. Yackly

2002-11-22

80

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The overall objective of this project is the three-phase development of an Early Entrance Coproduction Plant (EECP) that produces at least one product from at least two of the following three categories: Electric power (or heat); Fuels; and Chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or some other carbonaceous feedstock, such as petroleum coke. The objective of Phase I was to determine the feasibility and define the concept for the EECP located at a specific site and to develop a Research, Development, and Testing (RD and T) Plan for implementation in Phase II. This objective has now been accomplished. A specific site, Motiva Refinery in Port Arthur, Texas, has been selected as the location best suited for the EECP. The accomplishments of Phase I are discussed in detail in this Phase I Concept Report. A RD and T Plan and a preliminary project financing plan have been developed and are submitted separately from this report.

John S. Abughazaleh; Mushtaq Ahmed; Ashok Anand; John H. Anderson; Charles Benham; Fred D. Brent; Thomas E. Chance; William K. Davis; Raymond F. Drnevich; Larry Hall; Ming He; Stephen A. Lang; David Mintner; Wendy Moore; Jimmy O. Ong; George Potoczniak; Adela G. Sanchez; Charles H. Schrader; Lalit S. Shah; Kalapi D. Sheth; Phil J. Shires; Rae Song

2001-05-17

81

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal or coal in combination with some other carbonaceous feedstock. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site and to develop a Research, Development, and Test Plan (RD and T) for implementation in Phase II. The objective of Phase II is to conduct RD and T as outlined in the Phase I RD and T Plan to enhance the development and commercial acceptance of Coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and other feedstocks. The objective of Phase III is to develop an engineering design package and a financing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information that will be needed to move the EECP forward to detailed design, construction, and operation by industry.

Lalit S. Shah; William K. Davis

2000-05-01

82

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site and to develop a Research, Development, and Testing Plan (RD and T) for implementation in Phase II. The objective of Phase II is to implement the RD and T as outlined in the Phase I RD and T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information that will be needed to move the EECP forward to detailed design, construction, and operation by industry.

John S. Abughazaleh; Mushtaq Ahmed; Ashok Anand; John H. Anderson; Charles Benham; Fred D. Brent; Thomas E. Chance; William K. Davis; Raymond F. Drnevich; Larry Hall; Ming He; Stephen A. Lang; Jimmy O. Ong; Sarah J. Patel; George Potoczniak; Adela G. Sanchez; Charles H. Schrader; Lalit S. Shah; Phil J. Shires; Rae Song

2001-02-15

83

Seed dormancy distribution: explanatory ecological factors  

PubMed Central

Background and Aims Knowledge of those traits that vary with latitude should be helpful in predicting how they may evolve locally under climate change. In the sea beet Beta vulgaris ssp. maritima, seed dormancy largely controls the timing of germination, is highly heritable and varies geographically; it is therefore thought to be selected by climate. The aim here was to characterize the variation in seed dormancy among sea beet populations across the French distribution area, as well as the ecological factors in situ that are correlated with and that could therefore select for seed dormancy. The relative importance of genetic inheritance vs. non-genetic variation is also evaluated. Methods The proportions of dormant seeds from 85 natural populations encompassing different climates over the whole French distribution area were measured under controlled conditions. Germination phenology was observed in a common garden experiment. Dormancy variation of seeds collected in situ was compared with that of seeds collected on plants grown in the greenhouse. Key Results The proportions of dormant seeds in the greenhouse were highly variable, covering almost the entire range from 0 to 1, and followed a geographical pattern from lower dormancy at high latitudes to high dormancy at low latitudes. The distribution of dormancy was positively correlated with yearly temperatures, especially summer temperatures. Minimum temperatures in winter did not significantly explain the trait variation. The genetic component of the total variation was significant and is probably completed by an important adjustment to the local conditions brought about by maternal adaptive phenotypic plasticity. Conclusions Dormancy in sea beet could be interpreted as a way to limit summer germination and spread germination over the first autumn and spring or following autumns. This highly heritable trait has the potential to evolve in the relatively near future because of climate change. PMID:22952378

Wagmann, Kristen; Hautekèete, Nina-Coralie; Piquot, Yves; Meunier, Cécile; Schmitt, S. Eric; Van Dijk, Henk

2012-01-01

84

Phylogenetic analysis and molecular evolution of the dormancy associated MADS-box genes from peach  

PubMed Central

Background Dormancy associated MADS-box (DAM) genes are candidates for the regulation of growth cessation and terminal bud formation in peach. These genes are not expressed in the peach mutant evergrowing, which fails to cease growth and enter dormancy under dormancy-inducing conditions. We analyzed the phylogenetic relationships among and the rates and patterns of molecular evolution within DAM genes in the phylogenetic context of the MADS-box gene family. Results The peach DAM genes grouped with the SVP/StMADS11 lineage of type II MIKCC MADS-box genes. Phylogenetic analyses suggest that the peach SVP/StMADS11-like gene family, which contains significantly more members than annual model plants, expanded through serial tandem gene duplication. We found evidence of strong purifying selection acting to constrain functional divergence among the peach DAM genes and only a single codon, located in the C-terminal region, under significant positive selection. Conclusion Because all DAM genes are expressed in peach and are subjected to strong purifying selection we suggest that the duplicated genes have been maintained by subfunctionalization and/or neofunctionalization. In addition, this pattern of selection suggests that the DAM genes are important for peach growth and development. PMID:19558704

Jiménez, Sergio; Lawton-Rauh, Amy L; Reighard, Gregory L; Abbott, Albert G; Bielenberg, Douglas G

2009-01-01

85

Differential floral development and gene expression in grapevines during long and short photoperiods suggests a role for floral genes in dormancy transitioning.  

PubMed

Daylength is an important environmental cue for synchronizing growth, flowering, and dormancy with seasonality. As many floral development genes are photoperiod regulated, it has been suggested that they could have a regulatory role in bud endodormancy. Therefore, the influence of photoperiod was studied on inflorescence primordia differentiation and floral pathway related gene expression during the development of overwintering buds in Vitis riparia and V. spp. 'Seyval'. Photoperiod treatments were imposed 35 days after budbreak, and histological and transcriptomic analyses were conducted during the subsequent 42 days of bud development. Long day (LD, 15 h) and short day (SD, 13 h) buds were floral competent by 21 days of photoperiod treatment (56 days after budbreak); however, the floral meristem developed faster in LD than in SD buds. Analysis of 132 floral pathway related genes represented on the Affymetrix Grape Genome array indicated 60 were significantly differentially expressed between photoperiod treatments. Genes predominantly related to floral transition or floral meristem development were identified by their association with distinct grape floral meristem development and an expression pattern in LD consistent with their previously identified roles in flowering literature. Genes with a potential dual role in floral development and dormancy transitioning were identified using photoperiod induced differences in floral development between LD and SD buds and uncharacteristic gene expression trends in relation to floral development. Candidate genes with the potential to play a dual role in SD dormancy induction include circadian rhythm or flowering transition related genes: AP2, BT1, COL-13, EIN3, ELF4, DDTR, GAI and HY5. PMID:20151315

Sreekantan, Lekha; Mathiason, Kathy; Grimplet, Jérôme; Schlauch, Karen; Dickerson, Julie A; Fennell, Anne Y

2010-05-01

86

Genetic analysis of embryo dormancy. Final report  

SciTech Connect

Primary dormancy is the inability of mature seed to immediately germinate until specific environmental stimuli are perceived that predict that future conditions will support plant growth and seed set. The analysis of abscisic acid deficient and insensitive mutants, in particular in Arabidopsis, suggests that embryo abscisic acid may be directly involved in the development of primary dormancy. Other studies implicate the continued accumulation of LEA proteins as inhibiting germination in dormant embryos. The results of these physiological, molecular and genetic approaches are complex and equivocal. There is a real need for approaches that test the separate nature of vivipary inhibition and primary dormancy and deliberately seed to decouple and dissect them. These approaches should be of help in understanding both late embryo development and primary dormancy. The approach taken here is to directly isolate mutants of Arabidopsis that appear to be deficient only in primary dormancy, that is fresh seed that germinate rapidly without the normally-required cold-stratification. The authors have isolated at least 8 independent, rapidly germinating RGM mutants of Arabidopsis. All others aspects of plant growth and development appear normal in these lines, suggesting that the rgm mutants are defective only in the establishment or maintenance of primary dormancy. At least one of these may be tagged with T-DNA. In addition, about 50 RGM isolates have been recovered from EMS-treated seed.

Galau, G.

1998-09-01

87

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

In 1999, the U. S. Department of Energy (DOE) awarded a Cooperative Agreement to Texaco Energy Systems Inc. to provide a preliminary engineering design of an Early Entrance Coproduction Plant (EECP). Since the award, continuous and diligent work has been undertaken to achieve the design of an economical facility that makes strides toward attaining the goal of DOE's Vision 21 Program. The objective of the EECP is to convert coal and/or petroleum coke to power while coproducing transportation fuels, chemicals, and useful utilities such as steam. This objective is being pursued in a three-phase effort through the partnership of the DOE with prime contractor Texaco Energy Systems, LLC. (TES), the successor to Texaco Energy Systems, Inc. The key subcontractors to TES include General Electric (GE), Praxair, and Kellogg Brown and Root. ChevronTexaco provided gasification technology and Rentech Inc.'s Fischer-Tropsch (F-T) technology that has been developed for non-natural gas sources. GE provided gas turbine technology for the combustion of low energy content gas. Praxair provided air separation technology and KBR provided engineering to integrate the facility. A conceptual design was completed in Phase I and the report was accepted by the DOE in May 2001. The Phase I work identified risks and critical research, development, and testing that would improve the probability of technical success of the EECP. The objective of Phase II was to mitigate the risks by executing research, development, and testing. Results from the Phase II work are the subject of this report. As the work of Phase II concluded, it became evident that sufficient, but not necessarily complete, technical information and data would be available to begin Phase III - Preliminary Engineering Design. Work in Phase II requires additional technical development work to correctly apply technology at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The decision to proceed with Phase III centers on locating a new site and favorable commercial and economic factors.

John Anderson; Charles Schrader

2004-01-26

88

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC or TES (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, Inc., GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. During Phase I, a design basis for the Fischer-Tropsch Synthesis section was developed based on limited experience with the specified feed gas and operating conditions. The objective of this Task in Phase II RD&T work was to confirm the performance of the F-T reactor at the set design conditions. Although much of the research, development, and testing work were done by TES outside of this project, several important issues were addressed in this phase of the project. They included Rejuvenation/Regeneration of the Fischer-Tropsch Catalyst, online Catalyst Withdrawal and Addition from the synthesis reactor, and the Fischer-Tropsch Design Basis Confirmation. In Phase III the results from these RD&T work will be incorporated in developing the engineering design package. This Topical Report documents the Phase II RD&T work that was completed for this task.

David Storm; Govanon Nongbri; Steve Decanio; Ming He; Lalit Shah; Charles Schrader; Earl Berry; Peter Ricci; Belma Demirel; Charles Benham; Mark Bohn

2004-01-12

89

Identification and analysis of phosphorylation status of proteins in dormant terminal buds of poplar  

PubMed Central

Background Although there has been considerable progress made towards understanding the molecular mechanisms of bud dormancy, the roles of protein phosphorylation in the process of dormancy regulation in woody plants remain unclear. Results We used mass spectrometry combined with TiO2 phosphopeptide-enrichment strategies to investigate the phosphoproteome of dormant terminal buds (DTBs) in poplar (Populus simonii × P. nigra). There were 161 unique phosphorylated sites in 161 phosphopeptides from 151 proteins; 141 proteins have orthologs in Arabidopsis, and 10 proteins are unique to poplar. Only 34 sites in proteins in poplar did not match well with the equivalent phosphorylation sites of their orthologs in Arabidopsis, indicating that regulatory mechanisms are well conserved between poplar and Arabidopsis. Further functional classifications showed that most of these phosphoproteins were involved in binding and catalytic activity. Extraction of the phosphorylation motif using Motif-X indicated that proline-directed kinases are a major kinase group involved in protein phosphorylation in dormant poplar tissues. Conclusions This study provides evidence about the significance of protein phosphorylation during dormancy, and will be useful for similar studies on other woody plants. PMID:22074553

2011-01-01

90

Subtractive cDNA Libraries Identify Differentially Expressed Genes in Dormant and Growing Buds of Leafy Spurge ( Euphorbia esula )  

Microsoft Academic Search

Two subtractive cDNA libraries were developed to study genes associated with bud dormancy (reverse library) and initiation\\u000a of shoot growth (forward library) in leafy spurge. To identify unique sequences represented in each library, 15744 clones\\u000a were screened to reduce the level of redundancy within both libraries. A total of 516 unique sequences were obtained from\\u000a 2304 minimally redundant clones. Radioactive

Ying Jia; James V. Anderson; David P. Horvath; Yong-Qiang Gu; Rodney G. Lym; Wun S. Chao

2006-01-01

91

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The 1999 U. S. Department of Energy (DOE) award to Texaco Energy Systems Inc. (presently Texaco Energy Systems LLC, a subsidiary of ChevronTexaco) was made to provide a Preliminary Engineering Design of an Early Entrance Coproduction Plant (EECP). Since the award presentation, work has been undertaken to achieve an economical concept design that makes strides toward the DOE Vision 21 goal. The objective of the EECP is to convert coal and/or petroleum coke to electric power plus transportation fuels, chemicals and useful utilities such as steam. The use of petroleum coke was added as a fuel to reduce the cost of feedstock and also to increase the probability of commercial implementation of the EECP concept. This objective has been pursued in a three phase effort through the partnership of the DOE with prime contractor Texaco Energy Systems LLC and subcontractors General Electric (GE), Praxair, and Kellogg Brown and Root (KBR). ChevronTexaco is providing gasification technology and Rentech's Fischer-Tropsch technology that has been developed for non-natural gas feed sources. GE is providing gas turbine technology for the combustion of low energy content gas. Praxair is providing air separation technology, and KBR is providing engineering to integrate the facility. The objective of Phase I was to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. Phase I Preliminary Concept Report was completed in 2000. The Phase I Preliminary Concept Report was prepared based on making assumptions for the basis of design for various technologies that are part of the EECP concept. The Phase I Preliminary Concept Report was approved by the DOE in May 2001. The Phase I work identified technical and economic risks and critical research, development, and testing that would improve the probability of the technical and economic success of the EECP. The Project Management Plan (Task 1) for Phase II was approved by the DOE in 2001. The results of RD&T efforts for Phase II are expected to improve the quality of assumptions made in Phase I for basis of design for the EECP concept. The RD&T work plan (Task 2 and 3) for Phase II has been completed. As the RD&T work conducted during Phase II concluded, it became evident that sufficient, but not necessarily complete, technical information and data would be available to begin Phase III - Basic Engineering Design. Also due to the merger of Chevron and Texaco, the proposed refinery site for the EECP was not available. It became apparent that some additional technical development work would be needed to correctly apply the technology at a specific site. The objective of Task 4 of Phase II is to update the concept basis of design produced during Phase I. As part of this task, items that will require design basis changes and are not site dependent have been identified. The team has qualitatively identified the efforts to incorporate the impacts of changes on EECP concept. The design basis has been modified to incorporate those changes. The design basis changes for those components of EECP that are site and feedstock dependent will be done as part of Phase III, once the site has been selected.

Charles Benham; Mark Bohn; John Anderson; Earl Berry; Fred Brent; Ming He; Randy Roberts; Lalit Shah; Marjan Roos

2003-09-15

92

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are TES (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. During Phase I the team identified the integration of the water produced in the F-T synthesis section with the gasification section as an area of potential synergy. By utilizing the F-T water in the petroleum coke slurry for the gasifier, the EECP can eliminate a potential waste stream and reduce capital costs. There is a low technical risk for this synergy, however, the economic risk, particularly in regards to the water, can be high. The economic costs include the costs of treating the water to meet the locally applicable environmental standards. This option may require expensive chemicals and treatment facilities. EECP Phase II included tests conducted to confirm the viability of integrating F-T water in the slurry feed for the gasifier. Testing conducted at ChevronTexaco's Montebello Technology Center (MTC) included preparing slurries made using petroleum coke with F-T water collected at the LaPorte Alternative Fuels Development Unit (AFDU). The work included bench scale tests to determine the slurry ability of the petroleum coke and F-T water. The results of the tests show that F-T water does not adversely affect slurries for the gasifier. There are a few cases where in fact the addition of F-T water caused favorable changes in viscosity of the slurries. This RD&T task was executed in Phase II and results are reported herein.

Abdalla H. Ali; Raj Kamarthi; John H. Anderson; Earl R. Berry; Charles H. Schrader; Lalit S. Shah

2003-04-16

93

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC (TES), a subsidiary of ChevronTexaco, General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, Inc. GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. Each of the EECP subsystems were assessed for technical risks and barriers. A plan was identified to mitigate the identified risks (Phase II RD&T Plan, October 2000). The RD&T Plan identified catalyst/wax separation as a potential technical and economic risk. To mitigate risks to the proposed EECP, Phase II RD&T included tests of an alternative (to Rentech's Dynamic Settler) primary catalyst/wax separation device and secondary catalyst/wax separation systems. The team evaluated multiple technologies for both primary and secondary catalyst/wax separation. Based on successful testing at Rentech (outside of DOE funding) and difficulties in finalizing a contract to demonstrate alternative primary catalyst/wax separation technology (using magnetic separation technology), ChevronTexaco has selected the Rentech Dynamic Settler for primary catalyst/wax separation. Testing has shown the Dynamic Settler is capable of producing filtrate exceeding the proposed EECP primary catalyst/wax separation goal of less than 0.1 wt%. The LCI Scepter{reg_sign} Microfiltration system appeared to be best suited for producing a filtrate that met the EECP secondary catalyst/wax separation standards of 10 parts per million (weight) [ppmw]. The other technologies, magnetic separation and electrostatic separation, were promising and able to reduce the solids concentrations in the filtrate. Additional RD&T will be needed for magnetic separation and electrostatic separation technologies to obtain 10 ppmw filtrate required for the proposed EECP. The Phase II testing reduces the technical and economic risks and provides the information necessary to proceed with the development of an engineering design for the EECP Fischer-Tropsch catalyst/wax separation system.

John Anderson; Mark Anselmo; Earl Berry; Mark Bohn; Roko Bujas; Ming He; Ken Kwik; Charles H. Schrader; Lalit Shah; Dennis Slater; Donald Todd; Don Wall

2003-08-21

94

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to its detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC (TES) (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR). The work was under cooperative agreements with the U.S. Department of Energy (DOE). TES is providing the gasification technology and the Fischer-Tropsch (F-T) technology developed by Rentech Inc., GE is providing the combustion turbine technology, Praxair is providing the air separation technology, and KBR is providing overall engineering. Each of the EECP's subsystems was assessed for technical risks and barriers in Phase I. A plan was identified to mitigate the identified risks (Phase II RD&T Plan, October 2000). The RD&T Plan identified catalyst/wax separation as a potential technical and economic risk. To mitigate risks to the proposed EECP concept, Phase II RD&T included tests for secondary catalyst/wax separation systems as part of Task 2.3--Catalyst/Wax Separation. The LCI Scepter{reg_sign} Microfiltration system was determined to be best suited for producing a filtrate that met the EECP secondary catalyst/wax separation standards of producing F-T wax containing less than10 ppmw solids. As part of task 2.3, micro-filtration removal efficiencies and production rates for two FT feeds, Rentech Inc. bubble column reactor (BCR) product and LaPorte Alternative Fuels Development Unit (AFDU) product, were evaluated. Based on comparisons between the performances of these two materials, the more readily available LaPorte AFDU material was judged an acceptable analog to the BCR material that would be produced in a larger-scale F-T synthesis. The present test was initiated to obtain data in an extended range of concentration for use in the scale-up design of the secondary catalyst/wax separation system that would be operating at the EECP capacity.

John Anderson; Mark Anselmo; Earl Berry; Mark Bohn; Ming He; Charles H. Schrader; Lalit Shah; Donald Todd; Robert Schavey

2004-01-12

95

The inheritance of seed dormancy in Sinapis arvensis L  

Microsoft Academic Search

Selection for dormant and non-dormant seed in Sinapis arvensis was carried to the seventh and fourteenth generation, respectively. Crosses between the dormant and non-dormant lines clearly showed both a maternal and an embryonic component of seed dormancy. A model for the number of alleles controlling dormancy was constructed and tested. The maternal component of dormancy was shown to be controlled

K Garbutt; J R Witcombe

1986-01-01

96

Tansley review Seed dormancy and the control of germination  

E-print Network

Tansley review Seed dormancy and the control of germination William E. Finch-Savage1 and Gerhard This section on applied aspects of the control of seed germination by dormancy is an additional part the seed at the molecular level? 5. Applied aspects of the control of germination by seed dormancy Seeds

Leubner, Gerhard

97

Hormonal and molecular events during seed dormancy release and germination  

E-print Network

Hormonal and molecular events during seed dormancy release and germination Gerhard Leubner on Seeds, Salamanca, Spain, 12-16 May 2002 Symposium Seed Dormancy and Germination #12;Leubner-Metzger (2003) - page 2 Introduction Seed germination of species with 'coat-imposed' dormancy is determined

Leubner, Gerhard

98

Studies in Wild Oat Seed Dormancy  

PubMed Central

Seed of Avena fatua were shown to exhibit a characteristic loss of dormancy during dry storage at 25 C, whereas similar seed stored at 5 C maintained dormancy. 2-Chloroethylphosphonic acid was shown to increase germination of partly dormant seed imbibed under certain temperature regimes; a similar effect could not be established for fully dormant or fully nondormant seed. Using gas-liquid chromatography, natural ethylene levels were followed during imbibition of fully dormant and nondormant seed. A large peak in production was observed in the period prior to radicle emergence in the case of the nondormant seed. Measurements of ethylene production taken at 15 C, following periods of after-ripening in moist soil at either 5 or 25 C, indicated that endogenous production was unlikely to be a main cause of dormancy breakage in this species. The possibility that endogenous ethylene could play a role in natural dormancy breakage in aged seeds is discussed. The practical possibilities of 2-chloroethylphosphonic acid as a dormancy breaking agent in a field situation are outlined. PMID:16661675

Adkins, Stephen W.; Ross, James D.

1981-01-01

99

EARLY ENTRANCE COPRODUCTION PLANT  

SciTech Connect

The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC or TES (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. Each of the EECP subsystems was assessed for technical risks and barriers. A plan was developed to mitigate the identified risks (Phase II RD&T Plan, October 2000). Phase II RD&T Task 2.6 identified as potential technical risks to the EECP the fuel/engine performance and emissions of the F-T diesel fuel products. Hydrotreating the neat F-T diesel product reduces potentially reactive olefins, oxygenates, and acids levels and alleviates corrosion and fuel stability concerns. Future coproduction plants can maximize valuable transportation diesel by hydrocracking the F-T Synthesis wax product to diesel and naphtha. The upgraded neat F-T diesel, hydrotreater F-T diesel, and hydrocracker F-T diesel products would be final blending components in transportation diesel fuel. Phase II RD&T Task 2.6 successfully carried out fuel lubricity property testing, fuel response to lubricity additives, and hot-start transient emission tests on a neat F-T diesel product, a hydrocracker F-T diesel product, a blend of hydrotreater and hydrocracker F-T diesel products, and a Tier II California Air Resources Board (CARB)-like diesel reference fuel. Only the neat F-T diesel passed lubricity inspection without additive while the remaining three fuel candidates passed with conventional additive treatment. Hot-start transient emission tests were conducted on the four fuels in accordance with the U.S. Environmental Protection Agency (EPA) Federal Test Procedure (FTP) specified in Code of Federal Regulations, Title 40, Part 86, and Subpart N on a rebuilt 1991 Detroit Diesel Corporation Series 60 heavy-duty diesel engine. Neat F-T diesel fuel reduced oxides of nitrogen (NO{sub x}), total particulate (PM), hydrocarbons (HC), carbon monoxide (CO), and the Soluble Organic Fraction (SOF) by 4.5%, 31%, 50%, 29%, and 35%, respectively, compared to the Tier II CARB-like diesel. The hydrocracker F-T diesel product and a blend of hydrocracker and hydrotreater F-T diesel products also reduced NO{sub x}, PM, HC, CO and SOF by 13%, 16% to 17%, 38% to 63%, 17% to 21% and 21% to 39% compared to the Tier II CARB-like diesel. The fuel/engine performance and emissions of the three F-T diesel fuels exceed the performance of a Tier II CARB-like diesel. Phase II RD&T Task 2.6 successfully met the lubricity property testing and F-T diesel fuel hot-start transient emissions test objectives. The results of the testing help mitigate potential economic risks on obtaining a premium price for the F-T diesel fuel

Fred D. Brent; Lalit Shah; Earl Berry; Charles H. Schrader; John Anderson; J. Erwin; Matthew G. Banks; Terry L. Ullman

2004-01-12

100

Transcript profiling in Vitis riparia during chilling requirement fulfillment reveals coordination of gene expression patterns with optimized bud break.  

PubMed

Endodormant grapevine buds require a period of chilling before they break and begin to grow. Custom Vitis bud cDNA microarrays (9,216 features) were used to examine gene expression patterns in overwintering Vitis riparia buds during 2,000 h of 4 degrees C chilling. Three-node cuttings collected concurrently with buds were monitored to determine dormancy status. Chilling requirement was fulfilled after 1,500 h of chilling; however, 2,000 h of chilling significantly increased the rate of bud break. Microarray analysis identified 1,469 significantly differentially expressed (p value < 0.05) array features when 1,000, 1,500, and 2,000 h of chilling were compared to 500 h of chilling. Functional classification revealed that the majority of genes were involved in metabolism, cell defense/stress response, and genetic information processing. The number of significantly differentially expressed genes increased with chilling hour accumulation. The expression of a group of 130 genes constantly decreased during the chilling period. Up-regulated genes were not detected until the later stages of chilling accumulation. Hierarchical clustering of non-redundant expressed sequence tags revealed inhibition of genes involved in carbohydrate and energy metabolism and activation of genes involved in signaling and cell growth. Clusters with expression patterns associated with increased chilling and bud break were identified, indicating several candidate genes that may serve as indicators of bud chilling requirement fulfillment. PMID:18633655

Mathiason, Kathy; He, Dong; Grimplet, Jérôme; Venkateswari, J; Galbraith, David W; Or, Etti; Fennell, Anne

2009-02-01

101

On dormancy strategies in tardigrades.  

PubMed

In this review we analyze the dormancy strategies of metazoans inhabiting "hostile to life" habitats, which have a strong impact on their ecology and in particular on the traits of their life history. Tardigrades are here considered a model animal, being aquatic organisms colonizing terrestrial habitats. Tardigrades evolved a large variety of dormant stages that can be ascribed to diapause (encystment, cyclomorphosis, resting eggs) and cryptobiosis (anhydrobiosis, cryobiosis, anoxibiosis). In tardigrades, diapause and cryptobiosis can occur separately or simultaneously, consequently the adoption of one adaptive strategy is not necessarily an alternative to the adoption of the other. Encystment and cyclomorphosis are characterized by seasonal cyclic changes in morphology and physiology of the animals. They share several common features and their evolution is strictly linked to the molting process. A bet-hedging strategy with different patterns of egg hatching time has been observed in a tardigrade species. Four categories of eggs have been identified: subitaneous, delayed-hatching, abortive and diapause resting eggs, which needs a stimulus to hatch (rehydration after a period of desiccation). Cryptobiotic tardigrades are able to withstand desiccation (anhydrobiosis) and freezing (cryobiosis) at any stage of their life-cycle. This ability involves a complex array of factors working at molecular (bioprotectans), physiological and structural levels. Animal survival and the accumulation of molecular damage are related to the time spent in the cryptobiotic state, to the abiotic parameters during the cryptobiotic state, and to the conditions during initial and final phases of the process. Cryptobiosis evolved independently at least two times in tardigrades, in eutardigrades and in echiniscoids. Within each evolutionary line, the absence of cryptobiotic abilities is more related to selective pressures to local habitat adaptation than to phylogenetic relationships. The selective advantages of cryptobiosis (e.g. persistency in "hostile to life" habitats, reduction of competitors, parasites and predators, escaping in time from stressful conditions) could explain the high tardigrade species diversity and number of specimens found in habitats that dry out compared to freshwater habitats. PMID:21402076

Guidetti, Roberto; Altiero, Tiziana; Rebecchi, Lorena

2011-05-01

102

Circadian Clock Components Regulate Entry and Affect Exit of Seasonal Dormancy as Well as Winter Hardiness in Populus Trees1[W][OA  

PubMed Central

This study addresses the role of the circadian clock in the seasonal growth cycle of trees: growth cessation, bud set, freezing tolerance, and bud burst. Populus tremula × Populus tremuloides (Ptt) LATE ELONGATED HYPOCOTYL1 (PttLHY1), PttLHY2, and TIMING OF CAB EXPRESSION1 constitute regulatory clock components because down-regulation by RNA interference of these genes leads to altered phase and period of clock-controlled gene expression as compared to the wild type. Also, both RNA interference lines show about 1-h-shorter critical daylength for growth cessation as compared to the wild type, extending their period of growth. During winter dormancy, when the diurnal variation in clock gene expression stops altogether, down-regulation of PttLHY1 and PttLHY2 expression compromises freezing tolerance and the expression of C-REPEAT BINDING FACTOR1, suggesting a role of these genes in cold hardiness. Moreover, down-regulation of PttLHY1 and PttLHY2 causes a delay in bud burst. This evidence shows that in addition to a role in daylength-controlled processes, PttLHY plays a role in the temperature-dependent processes of dormancy in Populus such as cold hardiness and bud burst. PMID:20530613

Ibáñez, Cristian; Kozarewa, Iwanka; Johansson, Mikael; Ögren, Erling; Rohde, Antje; Eriksson, Maria E.

2010-01-01

103

A study of entrances to expressways  

E-print Network

for Entrance Ramp Design , . . . . . . . . . . . , . 16 A. Acceleration Lane B, Nerging Section 19 25 C, Heaving Section 39 V. Results 43 VI. Conclusions 48 VII, Bibliography ~ ~ ~ ~ ~ ~ ~ ~ ~ 50 LIST OF FIGURES Page I, Proposed Acceleration Lane... Design - 1942 . . . , . . . , . . . . , . . . , 7a II, Types of Entrances Recosssended by A. A. 8. 8, 4. . . . , . . . . , . , ~ 9a III. Griggs Road Entrance to Gulf Freeway 13 IV. Sketch of Proposed Entrance ~ 17 V, Normal Acceleration of Passenger...

Rollins, Albert Williamson

2012-06-07

104

Differential dormancy of co-occurring copepods  

NASA Astrophysics Data System (ADS)

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 and fixed across a species' range. Such interspecific and regional differences in life history traits need to be incorporated in models simulating Eastern Boundary Current pelagic ecosystem dynamics.

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

1998-08-01

105

Proteomic approach to analyze dormancy breaking of tree seeds.  

PubMed

In forest broadleaves from the temperate zone, a large number of species exhibit seed dormancy phenomena. Tree seeds show some of the most pronounced and complicated forms of dormancy in the plant kingdom. Many seeds are deeply physiologically dormant whatever their moisture level and age. However, dormancy can usually be overcome by a cold or warm stratification for several months. The transition from seed dormancy to germination is a multi-step process. In combination with the availability of genome sequence data, proteomics has opened up enormous possibilities for identifying the total set of expressed proteins as well as expression changes during dormancy breaking. The proteomic approach used for analysis of dormancy breaking of tree seeds offers new data allowing better understanding of the mechanism of deep physiological dormancy. The results of proteomic studies on dormancy breaking and the presence of abscisic and gibberellic acids in tree seeds (beech Fagus sylvatica L., Norway maple Acer platanoides L. and sycamore Acer pseudoplatanus L.), help to explain this process better. Most of the changes in protein expression were observed at the end of stratification and in the germinated seeds. This is the most active period of dormancy breaking when seeds pass from the quiescent state to germination. The analysis of the proteins' function showed that the mechanism of seed dormancy breaking involves many processes. Energy metabolism, proteasome, transcription, protein synthesis, signal transduction and methionine metabolism proteins have a special importance. PMID:20306286

Paw?owski, Tomasz Andrzej

2010-05-01

106

A molecular marker associated with low-temperature induction of dormancy in red osier dogwood (Cornus sericea).  

PubMed

Dormancy induction in temperate deciduous plants is thought to be regulated by short photoperiods, but low temperature has been shown to eliminate the short photoperiod requirement in northern ecotypes. An F2 population (191 plants) red osier dogwood (Cornus sericea L.) derived from a polycross of an F1 population produced from reciprocal crosses of the parental clonal ecotypes, Northwest Territories (NWT, 62 degrees N) and Utah (42 degrees N), was examined to identify molecular markers of temperature-induced endodormancy. Dormancy induction curves were generated for each individual in the F2 population and a standard point prior to vegetative maturity (i-VM) was inferred from the change in slope of the dormancy acquisition curve. Under Saskatoon, Saskatchewan field conditions (52 degrees N), the NWT ecotype entered i-VM on average 5-6 weeks before the Utah ecotype. Two sub-populations of the F2 population were distinguishable based on VM acquisition on exposure to low temperature but not to short photoperiods. A sequence characterized amplified region (SCAR) marker was developed that correctly (> 92%) identified individual plants within the F2 subpopulation that were responsive to low-temperature induction of VM. Timing of bud break was strongly associated with the timing of VM in the geographical ecotypes but not in the F2 population, indicating that these are separate traits under genetic control. PMID:17241980

Svendsen, Erl; Wilen, Ron; Stevenson, Robert; Liu, Rensong; Tanino, Karen K

2007-03-01

107

Ecological mechanisms involved in dormancy breakage in Ulex parviflorus seeds  

Microsoft Academic Search

Dormancy in the hard seed coats of Mediterranean species is considered a strategy that enables persistent seed banks to be\\u000a formed in the soil. An important factor related to seed coat fracture and dormancy breakage in Mediterranean ecosystems is\\u000a heat. Nevertheless, the effect of factors other than heat on dormancy breakage in these species has hardly been studied. To\\u000a investigate

M. J. Baeza; V. R. Vallejo

2006-01-01

108

CARBOHYDRATES AFFECT DORMANCY AND GROWTH IN UNDERGROUND BUDS OF LEAFY SPURGE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The term “low-carb diet” is frequently mentioned by a health conscious society interested in reducing carbohydrate intake. What are carbohydrates? In general, carbohydrates are either simple sugars like glucose, fructose, and sucrose (table sugar) or complexes of sugars like starch. Carbohydrates ar...

109

Apical dominance in saffron and the involvement of the branching enzymes CCD7 and CCD8 in the control of bud sprouting  

PubMed Central

Background In saffron (Crocus sativus), new corms develop at the base of every shoot developed from the maternal corm, a globular underground storage stem. Since the degree of bud sprouts influences the number and size of new corms, and strigolactones (SLs) suppress growth of pre-formed axillary bud, it was considered appropriate to investigate SL involvement in physiology and molecular biology in saffron. We focused on two of the genes within the SL pathway, CCD7 and CCD8, encoding carotenoid cleavage enzymes required for the production of SLs. Results The CsCCD7 and CsCCD8 genes are the first ones isolated and characterized from a non-grass monocotyledonous plant. CsCCD7 and CsCCD8 expression showed some overlapping, although they were not identical. CsCCD8 was highly expressed in quiescent axillary buds and decapitation dramatically reduced its expression levels, suggesting its involvement in the suppression of axillary bud outgrowth. Furthermore, in vitro experiments showed also the involvement of auxin, cytokinin and jasmonic acid on the sprouting of axillary buds from corms in which the apical bud was removed. In addition, CsCCD8 expression, but not CsCCD7, was higher in the newly developed vascular tissue of axillary buds compared to the vascular tissue of the apical bud. Conclusions We showed that production and transport of auxin in saffron corms could act synergistically with SLs to arrest the outgrowth of the axillary buds, similar to the control of above-ground shoot branching. In addition, jasmonic acid seems to play a prominent role in bud dormancy in saffron. While cytokinins from roots promote bud outgrowth. In addition the expression results of CsCCD8 suggest that SLs could positively regulate procambial activity and the development of new vascular tissues connecting leaves with the mother corm. PMID:24947472

2014-01-01

110

Dormancy of Heterodera glycines in Missouri  

PubMed Central

A 2-year study was conducted in field microplots to determine the relative importance of soybean phenology and soil temperature on induction of dormancy in Heterodera glycines in Missouri. Four near-isogenic soybean lines differing for maturity date were planted in microplots infested with a race 5 isolate of H. glycines. Soil temperature was monitored at a depth of 15 cm. Eggs of H. glycines, extracted from cysts collected monthly from each microplot, were used in hatching tests and bioassays to determine dormancy. Egg hatching and second-stage juvenile (J2) infectivity rates decreased sharply from their highest levels in midsummer (July-August) to a low level by October of each year and remained low (< 10% hatching and < 0.2 J2/cm root) until May or June of the following year. The patterns of numbers of females and eggs in the bioassays were similar. The decreases were not related to soil temperature and did not differ consistently among soybean isolines. The monophasic changes in all nematode responses with peak midsummer rates suggest that H. glycines produces one primary generation per year in central Missouri. Changes in hatching rates and the timing of minimum and maximum rates suggested that H. glycines eggs exhibit more than one type of dormancy. PMID:19277275

Yen, J. H.; Niblack, T. L.; Wiebold, W. J.

1995-01-01

111

Dormancy in potato tuber meristems: chemically induced cessation in dormancy matches the natural process based on transcript profiles.  

PubMed

Meristem dormancy in perennial plants is a developmental process that results in repression of metabolism and growth. The cessation of dormancy results in rapid growth and should be associated with the production of nascent transcripts that encode for gene products controlling for cell division and growth. Dormancy cessation was allowed to progress normally or was chemically induced using bromoethane (BE), and microarray analysis was used to demonstrate changes in specific transcripts in response to dormancy cessation before a significant increase in cell division. Comparison of normal dormancy cessation to BE-induced dormancy cessation revealed a commonality in both up and downregulated transcripts. Many transcripts that decrease as dormancy terminates are inducible by abscisic acid particularly in the conserved BURP domain proteins, which include the RD22 class of proteins and in the storage protein patatin. Transcripts that are associated with an increase in expression encoded for proteins in the oxoglutarate-dependent oxygenase family. We conclude that BE-induced cessation of dormancy initiates transcript profiles similar to the natural processes that control dormancy. PMID:18317824

Campbell, Michael; Segear, Erika; Beers, Lee; Knauber, Donna; Suttle, Jeffrey

2008-11-01

112

Dynamic thermal time model of cold hardiness for dormant grapevine buds  

PubMed Central

Background and Aims Grapevine (Vitis spp.) cold hardiness varies dynamically throughout the dormant season, primarily in response to changes in temperature. The development and possible uses of a discrete-dynamic model of bud cold hardiness for three Vitis genotypes are described. Methods Iterative methods were used to optimize and evaluate model parameters by minimizing the root mean square error between observed and predicted bud hardiness, using up to 22 years of low-temperature exotherm data. Three grape cultivars were studied: Cabernet Sauvignon, Chardonnay (both V. vinifera) and Concord (V. labruscana). The model uses time steps of 1 d along with the measured daily mean air temperature to calculate the change in bud hardiness, which is then added to the hardiness from the previous day. Cultivar-dependent thermal time thresholds determine whether buds acclimate (gain hardiness) or deacclimate (lose hardiness). Key Results The parameterized model predicted bud hardiness for Cabernet Sauvignon and Chardonnay with an r2 = 0·89 and for Concord with an r2 = 0·82. Thermal time thresholds and (de-)acclimation rates changed between the early and late dormant season and were cultivar dependent but independent of each other. The timing of these changes was also unique for each cultivar. Concord achieved the greatest mid-winter hardiness but had the highest deacclimation rate, which resulted in rapid loss of hardiness in spring. Cabernet Sauvignon was least hardy, yet maintained its hardiness latest as a result of late transition to eco-dormancy, a high threshold temperature required to induce deacclimation and a low deacclimation rate. Conclusions A robust model of grapevine bud cold hardiness was developed that will aid in the anticipation of and response to potential injury from fluctuations in winter temperature and from extreme cold events. The model parameters that produce the best fit also permit insight into dynamic differences in hardiness among genotypes. PMID:21212090

Ferguson, John C.; Tarara, Julie M.; Mills, Lynn J.; Grove, Gary G.; Keller, Markus

2011-01-01

113

ORIGINAL PAPER Environmental control of ovarian dormancy in natural  

E-print Network

and North America enter an adult ovarian dormancy in response to short days and low temperatures. The inde- pendent effects of temperature and day length in the determination of dormancy have been examined only populations, dor- mancy has been assessed at either a single short day or a single moderately low temperature

Oregon, University of

114

Role of metabolism in ABA homeostasis during potato tuber dormancy  

Technology Transfer Automated Retrieval System (TEKTRAN)

Endogenous hormones play a essential role in the regulation of potato tuber dormancy. Abscisic acid has been shown to be critically involved in tuber dormancy induction and maintenance. Genes encoding enzymes catalyzing the terminal steps of ABA synthesis and metabolism have been cloned from tuber...

115

[Uptake of (14C) leucine and protein synthesis in potato tuber buds and effect of abscisic acid on these processes].  

PubMed

The uptake of [14C] leucine and its incorporation into proteins of dormant and growing potato tuber buds were studied. It was found that the label uptake was increased at the beginning of the growth period, whereas the dynamics of this process were not changed in comparison with the dormant buds samples. The rate of [14C] leucine incorporation into proteins was increased in the growing buds; this increase was not, however, due to the increase in the uptake of the labelled precursor and was probably caused by activation of the protein synthesis. In contrast, the activation of protein synthesis was accompanied by changses is the dynamic incorporation of [14C] leucine into the protein at the end of dormancy. The effect of abscisic acid (10(-7) M) on the protein synthesis was not connected with its action of the uptake of labelled precursor and depended on the physiological state of buds and incubation time. A possible mechanism of regulatory effect of abscisic acid on protein synthesis in potato tuber buds is discussed. PMID:159728

Ladyzhenskaia, E P; Sukhova, L S; Korableva, N P; Metlitski?, L V

1979-10-01

116

School of Law Entrance Scholarships SCHOOL OF LAW ENTRANC E SCHOLARSHIP REGULATI ONS FOR 2009  

E-print Network

School of Law Entrance Scholarships SCHOOL OF LAW ENTRANC E SCHOLARSHIP REGULATI ONS FOR 2009 BACKGROUND The School of Law Entrance Scholarships were established by the School of Law to assist students with the cost of studying in their first year of law at the University of Waikato. Up to five Scholarships

Waikato, University of

117

"PROBATION AT ENTRANCE"--A STUDY.  

ERIC Educational Resources Information Center

PERSISTENCY AND SUCCESS OF 200 FALL, 1962, "PROBATION AT ENTRANCE" STUDENTS (WITH LESS THAN 2.0 GRADE POINT AVERAGE) WAS STUDIED. PERCENTAGE OF MEN AND WOMEN FROM VARIOUS HIGH SCHOOLS, MEDIAN ENTRANCE TEST SCORES, MAJOR FIELDS CHOSEN, AND EXTRACURRICULAR ACTIVITIES WERE ENUMERATED. THE MAJORITY OF STUDENTS CHOSE GOALS WITHIN THEIR ABILITY LEVELS,…

LUKE, ORRAL S.

118

Candidate cave entrances on Mars  

USGS Publications Warehouse

This paper presents newly discovered candidate cave entrances into Martian near-surface lava tubes, volcano-tectonic fracture systems, and pit craters and describes their characteristics and exploration possibilities. These candidates are all collapse features that occur either intermittently along laterally continuous trench-like depressions or in the floors of sheer-walled atypical pit craters. As viewed from orbit, locations of most candidates are visibly consistent with known terrestrial features such as tube-fed lava flows, volcano-tectonic fractures, and pit craters, each of which forms by mechanisms that can produce caves. Although we cannot determine subsurface extents of the Martian features discussed here, some may continue unimpeded for many kilometers if terrestrial examples are indeed analogous. The features presented here were identified in images acquired by the Mars Odyssey's Thermal Emission Imaging System visible-wavelength camera, and by the Mars Reconnaissance Orbiter's Context Camera. Select candidates have since been targeted by the High-Resolution Imaging Science Experiment. Martian caves are promising potential sites for future human habitation and astrobiology investigations; understanding their characteristics is critical for long-term mission planning and for developing the necessary exploration technologies.

Cushing, Glen E.

2012-01-01

119

Functional genomics of seed dormancy in wheat: advances and prospects.  

PubMed

Seed dormancy is a mechanism underlying the inability of viable seeds to germinate under optimal environmental conditions. To achieve rapid and uniform germination, wheat and other cereal crops have been selected against dormancy. As a result, most of the modern commercial cultivars have low level of seed dormancy and are susceptible to preharvest sprouting when wet and moist conditions occur prior to harvest. As it causes substantial loss in grain yield and quality, preharvest sprouting is an ever-present major constraint to the production of wheat. The significance of the problem emphasizes the need to incorporate an intermediate level of dormancy into elite wheat cultivars, and this requires detailed dissection of the mechanisms underlying the regulation of seed dormancy and preharvest sprouting. Seed dormancy research in wheat often involves after-ripening, a period of dry storage during which seeds lose dormancy, or comparative analysis of seeds derived from dormant and non-dormant cultivars. The increasing development in wheat genomic resources along with the application of transcriptomics, proteomics, and metabolomics approaches in studying wheat seed dormancy have extended our knowledge of the mechanisms acting at transcriptional and post-transcriptional levels. Recent progresses indicate that some of the molecular mechanisms are associated with hormonal pathways, epigenetic regulations, targeted oxidative modifications of seed mRNAs and proteins, redox regulation of seed protein thiols, and modulation of translational activities. Given that preharvest sprouting is closely associated with seed dormancy, these findings will significantly contribute to the designing of efficient strategies for breeding preharvest sprouting tolerant wheat. PMID:25309557

Gao, Feng; Ayele, Belay T

2014-01-01

120

Stratification Requirements for Seed Dormancy Alleviation in a Wetland Weed  

PubMed Central

Echinochloaoryzicola(syn.E. phyllopogon) is an exotic weed of California rice paddies that has evolved resistance to multiple herbicides. Elimination of seedlingsthroughcertain weed control methods can limit the spread of this weed, but is contingent on accurate predictions of germination and emergence timing, which are influenced by seed dormancy levels.In summer annuals, dormancy can often be relieved through stratification, a period of prolonged exposure to cold and moist conditions.We used population-based threshold models to quantify the effects of stratification on seed germination of four E. Oryzicola populations at a range of water potential (?) and oxygen levels. We also determined how stratification temperatures, moisture levels and durations contributed to dormancy release. Stratification released dormancy by decreasing base ? and hydrotimerequired for germination and by eliminating any germination sensitivity to oxygen. Stratification also increased average germination rates (GR), which were used as a proxy for relative dormancy levels. Alternating temperatures nearly doubled GR in all populations, indicating that seeds could be partially dormant despite achieving high final germination percentages. Stratification at ??=?0 MPa increased GR compared to stratification at lower water potentials, demonstrating that ? contributed to regulating dormancy release. Maximum GR occurred after 2-4 weeks of stratification at 0 MPa; GR were often more rapid for herbicide-resistant than for herbicide-susceptible seeds, implying greater dormancy in the latter. Manipulation of field conditions to promote dormancy alleviation of E. oryzicola seeds might improve the rate and uniformity of germination for seed bank depletion through seedling weed control. Our results suggest field soil saturation in winter would contribute towards E. oryzicola dormancy release and decrease the time to seedling emergence. PMID:24039714

Boddy, Louis G.; Bradford, Kent J.; Fischer, Albert J.

2013-01-01

121

Functional genomics of seed dormancy in wheat: advances and prospects  

PubMed Central

Seed dormancy is a mechanism underlying the inability of viable seeds to germinate under optimal environmental conditions. To achieve rapid and uniform germination, wheat and other cereal crops have been selected against dormancy. As a result, most of the modern commercial cultivars have low level of seed dormancy and are susceptible to preharvest sprouting when wet and moist conditions occur prior to harvest. As it causes substantial loss in grain yield and quality, preharvest sprouting is an ever-present major constraint to the production of wheat. The significance of the problem emphasizes the need to incorporate an intermediate level of dormancy into elite wheat cultivars, and this requires detailed dissection of the mechanisms underlying the regulation of seed dormancy and preharvest sprouting. Seed dormancy research in wheat often involves after-ripening, a period of dry storage during which seeds lose dormancy, or comparative analysis of seeds derived from dormant and non-dormant cultivars. The increasing development in wheat genomic resources along with the application of transcriptomics, proteomics, and metabolomics approaches in studying wheat seed dormancy have extended our knowledge of the mechanisms acting at transcriptional and post-transcriptional levels. Recent progresses indicate that some of the molecular mechanisms are associated with hormonal pathways, epigenetic regulations, targeted oxidative modifications of seed mRNAs and proteins, redox regulation of seed protein thiols, and modulation of translational activities. Given that preharvest sprouting is closely associated with seed dormancy, these findings will significantly contribute to the designing of efficient strategies for breeding preharvest sprouting tolerant wheat. PMID:25309557

Gao, Feng; Ayele, Belay T.

2014-01-01

122

Wheat seed proteins regulated by imbibition independent of dormancy status  

PubMed Central

Seed dormancy is an important trait in wheat (Trticum aestivum L.) and it can be released by germination-stimulating treatments such as after-ripening. Previously, we identified proteins specifically associated with after-ripening mediated developmental switches of wheat seeds from the state of dormancy to germination. Here, we report seed proteins that exhibited imbibition induced co-regulation in both dormant and after-ripened seeds of wheat, suggesting that the expression of these specific proteins/protein isoforms is not associated with the maintenance or release of seed dormancy in wheat. PMID:24084602

Park, Seokhoon; Rampitsch, Christof; Humphreys, Gavin D; Ayele, Belay T

2013-01-01

123

2013 Entrance Exam Guidelines Professional Degree Program  

E-print Network

, Biostatistics, Clinical Epidemiology, Health Economics, Health Communication, Mental Health, Health Sociology2013 Entrance Exam Guidelines Professional Degree Program School of Public Health (Professional Guidelines Professional Degree Program, School of Public Health (Professional Graduate School) Graduate

Miyashita, Yasushi

124

2014 Entrance Exam Guidelines Professional Degree Program  

E-print Network

, Biostatistics, Clinical Epidemiology, Health Economics, Health Communication, Mental Health, Health Sociology2014 Entrance Exam Guidelines Professional Degree Program School of Public Health (Professional Guidelines Professional Degree Program, School of Public Health (Professional Graduate School) Graduate

Miyashita, Yasushi

125

Eyeing emergence: modified treatments for terminating dormancy of conifer seeds.  

PubMed

Many seeds of coniferous species display a deep primary dormancy at maturity and require several weeks of pretreatment to produce seed populations that germinate in a vigorous and timely manner. Facilitating an efficient transition from dormancy to germination by devising improved protocols for dormancy breakage is not only important to conifer seed research, aiding in the study of the dormancy process itself, but is also of interest and applicability to commercial forest nursery operations. In the forests of British Columbia, Canada, several conifer species are well-adapted to their environment, with seeds needing to experience long durations in the moist state at cool or fluctuating temperatures. These include yellow-cedar (Callitropsis nootkatensis), western white pine (Pinus monticola), and true fir species, such as Pacific silver fir and subalpine fir (Abies amabilis and A. lasiocarpa, respectively). In this chapter, we discuss the development of new dormancy-breaking protocols for the aforementioned species that centre on the balance of several key aspects: (1) reducing the time needed to terminate dormancy in the seed population; (2) synchronicity of germination; (3) ease of use; (4) cost-effectiveness; and (5) repeatability. Where possible, any new or modified protocol should be further tested in relationship to promoting rapid seedling growth in a forest nursery greenhouse setting and after planting at natural stands. Based on the five criteria listed above, very significant improvements compared to traditional dormancy-breaking methods have been achieved for the targeted conifer species. Where tested (e.g. yellow-cedar), the modified dormancy-breaking treatments result in vigorous growth in the greenhouse and after planting at natural stands. PMID:21898249

Feurtado, J Allan; Kermode, Allison R

2011-01-01

126

Dormancy in the stem cell niche.  

PubMed

Tissues characterized by constant turnover contain post-mitotic, terminally differentiated cells originating from highly proliferative progenitors, which in turn derive from a relatively small population of stem cells. At the population level, self-renewal and differentiation are the possible outcomes of stem cell proliferation; overall, however, stem cells are quiescent if compared with their direct progeny. The recent discovery of a particularly quiescent, or dormant, subpopulation of hematopoietic stem cells (HSCs) raises a number of fundamental questions. As stem cell fate is influenced by the signals integrated by the stem cell niche, will dormant HSCs reside in specific dormant niches? Is the mechanism of dormancy common to multiple regenerating tissues or specific to the hematopoietic system? If cancer is maintained by a few cancer stem cells, do they also contain a subpopulation of dormant cells, and could this be exploited for therapeutic purposes? PMID:22429750

Sottocornola, Roberta; Lo Celso, Cristina

2012-01-01

127

Dormancy in the stem cell niche  

PubMed Central

Tissues characterized by constant turnover contain post-mitotic, terminally differentiated cells originating from highly proliferative progenitors, which in turn derive from a relatively small population of stem cells. At the population level, self-renewal and differentiation are the possible outcomes of stem cell proliferation; overall, however, stem cells are quiescent if compared with their direct progeny. The recent discovery of a particularly quiescent, or dormant, subpopulation of hematopoietic stem cells (HSCs) raises a number of fundamental questions. As stem cell fate is influenced by the signals integrated by the stem cell niche, will dormant HSCs reside in specific dormant niches? Is the mechanism of dormancy common to multiple regenerating tissues or specific to the hematopoietic system? If cancer is maintained by a few cancer stem cells, do they also contain a subpopulation of dormant cells, and could this be exploited for therapeutic purposes? PMID:22429750

2012-01-01

128

The perivascular niche regulates breast tumor dormancy  

PubMed Central

In a significant fraction of breast cancer patients, distant metastases emerge after years or even decades of latency. How disseminated tumor cells (DTCs) are kept dormant, and what ‘wakes them up’, are fundamental problems in tumor biology. To address these questions, we utilized metastasis assays in mice to show that dormant DTCs reside upon microvasculature of lung, bone marrow and brain. We then engineered organotypic microvascular niches to determine whether endothelial cells directly influence breast cancer cell (BCC) growth. These models demonstrated that endothelial-derived thrombospondin-1 induces sustained BCC quiescence. This suppressive cue was lost in sprouting neovasculature; time-lapse analysis showed that sprouting vessels not only permit, but accelerate BCC outgrowth. We confirmed this surprising result in dormancy models and in zebrafish, and identified active TGF-?1 and periostin as tumor-promoting, endothelial tip cell-derived factors. Our work reveals that stable microvasculature constitutes a ‘dormant niche,’ whereas sprouting neovasculature sparks micrometastatic outgrowth. PMID:23728425

Peinado, Héctor; Mori, Hidetoshi; Matei, Irina R.; Evason, Kimberley J.; Brazier, Hélène; Almeida, Dena; Koller, Antonius; Hajjar, Katherine A.; Stainier, Didier Y.R.; Chen, Emily I.; Lyden, David

2013-01-01

129

Effects of Dormancy Regulating Chemicals on Innate and Salinity Induced Dormancy in the Invasive Prosopis juliflora (Sw.) DC. Shrub  

Microsoft Academic Search

The effect of different types and concentrations of dormancy regulating chemicals (DRCs) on innate and induced dormancy was evaluated under optimal germination conditions in the invasive Prosopis juliflora shrub. Lower concentrations of gibberellic acid (0.3 mM) and kinetin (0.05 mM) were more effective in enhancing germination % and rate at higher concentrations of NaCl, but the reverse was true for thiourea. None

Ali-El-Keblawy; Fatima Al-Ansari; Awatif Al-Rawai

2005-01-01

130

Budding in the Dimorphic Fungus Phialophora dermatitidis  

PubMed Central

Ultrastructural comparisons of yeast and hyphal bud formation in Phialophora dermatitidis reveal that bud initiation is characterized by a blastic rupture of the outer portion of the yeast or hyphal wall and the emergence of a bud protuberance through the resulting opening. The wall of the emerging bud is continuous, with only an inner wall layer of the parental yeast or hypha. The outer, ruptured portion of the parental wall typically forms a collar around the constricted emergence region of the developing bud. The cytoplasm within the very young emerging bud invariably contains a small number of membrane-bound vesicles. The septum formed between the daughter bud and the parental yeast or hypha is a complete septum devoid of a septal pore, septal pore plug, or any associated Woronin bodies characteristic of simple septa of the moniliform or true hyphae. These observations suggest that yeast bud formation and lateral hyphal bud formation in the dimorphic fungus P. dermatitidis involve a growth process which occurs identically in both the yeast and mold phase of this human pathogenic organism. Images PMID:4717521

Grove, Stanley N.; Oujezdsky, Karen B.; Szaniszlo, Paul J.

1973-01-01

131

Cotton buds, momentum, and impulse  

NASA Astrophysics Data System (ADS)

Here is a simple experiment demonstrating impulse and momentum that was picked up from a Japanese presenter at a physics teacher conference held in Cebu City. We have not been able to trace the experiment farther and have never seen it in print. After student-author Nuñez demonstrated it during an exam on conducting demonstrations, we converted the qualitative idea into a quanitative experiment and even discovered some possibilities for student research. The lab is also suitable as homework, since it uses universally available "equipment" — cotton buds (swabs), drinking straws, and a ruler.

van den Berg, Ed; Nuñez, Jover; Guirit, Alfredo; van Huis, Cor

2000-01-01

132

Repellence of the red bud borer (Resseliella oculiperda) to grafted apple trees by impregnation of budding tape with essential oils  

Microsoft Academic Search

The red bud borer Resseliella oculiperda (Rübs.) is a pest insect of apple trees when rootstocks are grafted with scion buds by shield budding. The female midges are attracted to the wounds of the grafted buds where they lay their eggs. The larvae feed on the cambium and destroy the buds completely or partially, leading to bad union of the

Tol van R. W. H. M; Linden van der A; H. J. Swarts; J. H. Visser

2007-01-01

133

A novel preclinical murine model of immune-mediated metastatic dormancy  

PubMed Central

The mechanisms underlying cancer dormancy are poorly understood. We have developed a preclinical murine model in which immunosurveillance restrains spontaneous metastases in permanent dormancy. The model faithfully recapitulates human metastatic dormancy and may be useful to decipher the immune mechanisms constraining disease progression, thereby facilitating the development of novel immunotherapeutic approaches to control metastatic disease. PMID:25083338

Romero, Irene; Garrido, Federico; Garcia-Lora, Angel M

2014-01-01

134

Engineering seed dormancy by the modification of zeaxanthin epoxidase gene expression  

Microsoft Academic Search

Abscisic acid (ABA) is a plant hormone synthesized during seed development that is involved in the induction of seed dormancy. Delayed germination due to seed dormancy allows long-term seed survival in soil but is generally undesirable in crop species. Freshly harvested seeds of wild-type Nicotiana plumbaginifolia plants exhibit a clear primary dormancy that results in delayed germination, the degree of

Anne Frey; Corinne Audran; Elena Marin; Bruno Sotta; Annie Marion-Poll

1999-01-01

135

Physiology of Induction and Relaxation of Summer Dormancy in Perennial Grasses  

Microsoft Academic Search

The involvement of main environmental factors, such as day-length, temperature and water availability, in the imposition and relaxation of the summer dormancy stage in perennial grasses is reviewed. Adaptive value of variation in summer dormancy and differences between summer quiescence and summer dormancy are discussed. The role of high temperature in the inhibition of leaf growth and in the maintenance

J. Kigel; M. Ofir; A. Kon; D. P. Malinowski; W. E. Pinchak

136

Variation in Summer Dormancy in the Lilioid Geophyte Burchardia umbellata (Colchicaceae)  

Microsoft Academic Search

Plant dormancy is a form of phenotypic plasticity that minimizes exposure to seasonally stressful conditions. We examined variation in summer dormancy in two highland and two lowland populations of the lilioid geophyte Burchardia umbellatato test the prediction that facultative dormancy is advantageous in habitats with variable summer conditions. Consistent with this prediction fewer highland plants than lowland plants became dormant

Glenda Vaughton; Mike Ramsey

2001-01-01

137

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

Microsoft Academic Search

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. Dormancy is related to the amount of a hypothetical phytochrome receptor, which fluctuates

L. M. Vleeshouwers; H. J. Bouwmeester

2001-01-01

138

Dormancy and quiescence of skeletal muscle stem cells.  

PubMed

The skeletal muscle of vertebrates has a huge regenerative capacity. When destroyed after different types of injury, this organ can regenerate very quickly (less than 20 days following myotoxin injection in the mouse) ad integrum and repeatedly. The cell responsible for this regeneration is the so-called satellite cell, the muscle stem cell that lies on top of the muscle fibre, a giant, multinucleated cell that contains the contractile material. When injected in the muscle, satellite cells can efficiently differentiate into contractile muscle fibres. The satellite cell shows great therapeutic potential; and its regenerative capacity has triggered particular interest in the field of muscular degeneration.In this review we will focus on one particular property of the satellite cell: its quiescence and dormancy. Indeed adult satellite cells are quiescent; they lie between the basal lamina and the basement membrane of the muscle fibre, ready to proliferate, and fuse in order to regenerate myofibers upon injury. It has recently been shown that a subpopulation of satellite cells is able to enter dormancy in human and mice cadavers. Dormancy is defined by a low metabolic state, low mobility, and a long lag before division when plated in vitro, compared to quiescent cells. This definition is also based on current knowledge about long-term hematopoietic stem cells, a subpopulation of stem cells that are described as dormant based on the same criteria (rare division and low metabolism when compared to progeny which are dividing more often).In the first part of this review, we will provide a description of satellite cells which addresses their quiescent state. We will then focus on the uneven distribution of satellite cells in the muscle and describe evidence that suggests that their dormancy differs from one muscle to the next and that one should be cautious when making generalisations regarding this cellular state.In a second part, we will discuss the transition between active dividing cells in developing animals to quiescence. This mechanism could be used or amplified in the switch from quiescence to dormancy.In a third part, we will review the signals and dynamics that actively maintain the satellite cell quiescent. The in-depth understanding of these mechanisms is key to describing how dormancy relies on quiescent state of the cells.In a fourth part, we will deal with dormancy per se: how dormant satellite cells can be obtained, their characteristics, their metabolic profile, and their molecular signature as compared to quiescent cells. Here, we will highlight one of the most important recent findings: that quiescence is a prerequisite for the entry of the satellite cell into dormancy.Since dormancy is a newly discovered phenomenon, we will review the mechanisms responsible for quiescence and activation, as these two cellular states are better known and key to understanding satellite cell dormancy. This will allow us to describe dormancy and its prerequisites. PMID:25344673

Rocheteau, Pierre; Vinet, Mathilde; Chretien, Fabrice

2015-01-01

139

8. VIEW LOOKING SOUTH, SHOWING NORTH ENTRANCE HOUSE AND CENTRAL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. VIEW LOOKING SOUTH, SHOWING NORTH ENTRANCE HOUSE AND CENTRAL PAVILION, WITH SOUTH ENTRANCE HOUSE AND ENGINE HOUSE BEYOND - Fairmount Waterworks, East bank of Schuylkill River, Aquarium Drive, Philadelphia, Philadelphia County, PA

140

33 CFR 110.194 - Mobile Bay, Ala., at entrance.  

Code of Federal Regulations, 2014 CFR

...Navigable Waters 1 2014-07-01 2014-07-01 false Mobile Bay, Ala., at entrance. 110.194 Section 110.194... ANCHORAGE REGULATIONS Anchorage Grounds § 110.194 Mobile Bay, Ala., at entrance. (a) The anchorage...

2014-07-01

141

4. Light tower, interior from entrance, looking southeast Goat ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Light tower, interior from entrance, looking southeast - Goat Island Light Station, Goat Island, next to entrance to Cape Porpoise Harbor, just south of Trott Island, Cape Porpoise, York County, ME

142

Informed Consent for PGP Entrance Exam [Version #1  

E-print Network

Informed Consent for PGP Entrance Exam [Version #1] Title: Personal Genome Project Entrance Exam and therefore am providing informed consent for this questionnaire. Name: Email: HMS/HSDM Committee on Human

Church, George M.

143

Dormancy-associated MADS genes from the EVG locus of peach [Prunus persica (L.) Batsch] have distinct seasonal and photoperiodic expression patterns  

PubMed Central

Mapping and sequencing of the non-dormant evg mutant in peach [Prunus persica (L.) Batsch] identified six tandem-arrayed DAM (dormancy-associated MADS-box) genes as candidates for regulating growth cessation and terminal bud formation. To narrow the list of candidate genes, an attempt was made to associate bud phenology with the seasonal and environmental patterns of expression of the candidates in wild-type trees. The expression of the six peach DAM genes at the EVG locus of peach was characterized throughout an annual growing cycle in the field, and under controlled conditions in response to a long day–short day photoperiod transition. DAM1, 2, 4, 5, and 6 were responsive to a reduction in photoperiod in controlled conditions and the direction of response correlated with the seasonal timing of expression in field-grown trees. DAM3 did not respond to photoperiod and may be regulated by chilling temperatures. The DAM genes in peach appear to have at least four distinct patterns of expression. DAM1, 2, and 4 are temporally associated with seasonal elongation cessation and bud formation and are the most likely candidates for control of the evg phenotype. PMID:19553369

Li, Zhigang; Reighard, Gregory Lynn; Abbott, Albert Glenn; Bielenberg, Douglas Gary

2009-01-01

144

Axillary shoot bud development in selected Actinidia species  

Microsoft Academic Search

Development of shoot buds of 10 Actinidia species from inception at budbreak to full?size, dormant buds is described as an important prerequisite for understanding vine physiology. Bud diameter was measured, leaf initials, and axillary structures were identified and counted with a dissecting microscope. Areas of the subtending leaves were measured. Both shoot bud size and leaf area decreased from the

Angela M. Snowball

1997-01-01

145

Scarification and Germination Treatments Break Dormancy of Rubus Species  

Technology Transfer Automated Retrieval System (TEKTRAN)

The genus Rubus exhibits morphological diversity and a wide range of reproductive systems and habitats. Seeds of blackberry (subgenus Rubus) and raspberry (subg. Idaeobatus) have a deep dormancy caused by one or more mechanisms. Rubus seeds are normally enclosed in a hard schlerenchymatous endocar...

146

Microbial seed banks: the ecological and evolutionary implications of dormancy  

Microsoft Academic Search

Dormancy is a bet-hedging strategy used by a wide range of taxa, including microorganisms. It refers to an organism's ability to enter a reversible state of low metabolic activity when faced with unfavourable environmental conditions. Dormant microorganisms generate a seed bank, which comprises individuals that are capable of being resuscitated following environmental change. In this Review, we highlight mechanisms that

Stuart E. Jones; Jay T. Lennon

2011-01-01

147

INVITED REVIEW Plant hormone interactions during seed dormancy release  

E-print Network

- mation and growth of different plant organs. The plant hormones abscisic acid (ABA), gibberellins (GAINVITED REVIEW Plant hormone interactions during seed dormancy release and germination Birgit Kucera1 , Marc Alan Cohn2 and Gerhard Leubner-Metzger1 * 1 Institute of Biology II, Botany/Plant

Leubner, Gerhard

148

Ethylene, a key factor in the regulation of seed dormancy  

PubMed Central

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 ?L 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 crosstalk between hormones and other signals will be discussed. PMID:25346747

Corbineau, Françoise; Xia, Qiong; Bailly, Christophe

2014-01-01

149

Ecology of seed dormancy and germination in sedges ( Carex)  

Microsoft Academic Search

The genus Carex, with its wide distribution and large number of species yet with a rather uniform life history, is a very convenient group for comparative studies of germination ecology at the generic level. The combination of a strict or conditional primary dormancy, a light requirement for germination, low germination at constant temperatures, a positive response to diurnal temperature fluctuations

Wolfgang Schütz

2000-01-01

150

Perspectives of biotechnologies based on dormancy phenomenon for space researches  

NASA Astrophysics Data System (ADS)

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

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

151

Reconstitution of membrane budding with unilamellar vesicles  

PubMed Central

Enveloped virus particles select their lipid-protein components and egress by budding from the host cell membranes. The matrix protein of many enveloped viruses has been proposed as a crucial element for viral budding; however, molecular mechanisms behind membrane budding by the matrix protein are yet to be unraveled. Here we describe a set of in vitro functional reconstitution assays that allows quantitative evaluation of both, membrane binding and creation of membrane curvature by the matrix protein isolated from Newcastle Disease Virus. Individual budding events orchestrated by the matrix protein can be resolved in real time. The assays may be applied for direct reconstitution of the on-membrane action of cellular proteins involved in membrane curvature induction upon binding in vivo. PMID:19903550

Shnyrova, Anna V.; Zimmerberg, Joshua

2012-01-01

152

The dormant buds of Rhabdopleura compacta (Hemichordata).  

PubMed

Rhabdopleura has an overwintering stage that consists of two layers of cells surrounding a central yolk mass. This cellular part is surrounded by a thick electron dense capsule which is secreted by the bud itself. The capsule is probably impervious and protective to its contents. Blood vessels join the buds to the zooids of the colony. They form the probable route of transfer of yolk from the zooids to the dormant bud. The capsule of the dormant bud has some structural features in common with the black stolon of the adult zooids. The black stolon is probably formed in a manner similar to that which made the fusellar fabric of the periderm of fossil graptolities. PMID:1149105

Dilly, P N

1975-06-13

153

A New, Mushroom-shaped Budding Bacterium  

Microsoft Academic Search

A mushroom-shaped budding bacterium, isolated from fresh pond water, is unlike any previously described aquatic budding bacteria (Whittenbury & McLee, I 967 ; Hirsch & Rheinheimer, 1968 ; Staley, 1968). Its morphological 'life-cycle' and other properties are described. METHODS Media. The organism was grown routinely in glucose-salts medium (pH 6.9) of the follow- ing composition: (NH4)2S04, 0.1 % (w\\/v); NaCI,

R. WHITTENBURY; JUDITH M. NICOLL

1971-01-01

154

A local dormancy cline is related to the seed maturation environment, population genetic composition and climate  

PubMed Central

Background and Aims Seed dormancy varies within species in response to climate, both in the long term (through ecotypes or clines) and in the short term (through the influence of the seed maturation environment). Disentangling both processes is crucial to understand plant adaptation to environmental changes. In this study, the local patterns of seed dormancy were investigated in a narrow endemic species, Centaurium somedanum, in order to determine the influence of the seed maturation environment, population genetic composition and climate. Methods Laboratory germination experiments were performed to measure dormancy in (1) seeds collected from different wild populations along a local altitudinal gradient and (2) seeds of a subsequent generation produced in a common garden. The genetic composition of the original populations was characterized using intersimple sequence repeat (ISSR) PCR and principal co-ordinate analysis (PCoA), and its correlation with the dormancy patterns of both generations was analysed. The effect of the local climate on dormancy was also modelled. Key Results An altitudinal dormancy cline was found in the wild populations, which was maintained by the plants grown in the common garden. However, seeds from the common garden responded better to stratification, and their release from dormancy was more intense. The patterns of dormancy variation were correlated with genetic composition, whereas lower temperature and summer precipitation at the population sites predicted higher dormancy in the seeds of both generations. Conclusions The dormancy cline in C. somedanum is related to a local climatic gradient and also corresponds to genetic differentiation among populations. This cline is further affected by the weather conditions during seed maturation, which influence the receptiveness to dormancy-breaking factors. These results show that dormancy is influenced by both long-and short-term climatic variation. Such processes at such a reduced spatial scale highlight the potential of plants to adapt to fast environmental changes. PMID:23864001

Fernández-Pascual, Eduardo; Jiménez-Alfaro, Borja; Caujapé-Castells, Juli; Jaén-Molina, Ruth; Díaz, Tomás Emilio

2013-01-01

155

Genetic and environmental control of dormancy in white-grained wheat ( Triticum aestivum L.)  

Microsoft Academic Search

Grain dormancy in wheat is an important component of resistance to preharvest sprouting and hence an important trait for wheat\\u000a breeders. The significant influence of environment on the dormancy phenotype makes this trait an obvious target for marker-assisted-selection.\\u000a Closely related breeding lines, SUN325B and QT7475, containing a major dormancy QTL derived from AUS1408 located on chromosome\\u000a 4A, but substantially different

Daryl Mares; Judith Rathjen; Kolumbina Mrva; Judy Cheong

2009-01-01

156

A combined physical and physiological dormancy controls seasonal seedling emergence of Geranium robertianum.  

PubMed

Temperate forest herbs with seeds exhibiting both a physical and a physiological dormancy mechanism are rare, and knowledge on the factors regulating germination of these species is fragmentary. The biennial Geranium robertianum L. grows mainly in temperate woodlands, but can also be found in exposed habitats. Seedlings of G. robertianum are known to emerge from spring until autumn, but little is known about the environmental factors regulating germination. In this study, phenology of seedling emergence and of physical dormancy loss was examined for seeds buried at shaded or sunny exposed locations. The role of temperature in regulating dormancy and germination was analysed by incubating seeds in temperature sequences simulating temperatures that seeds experience in nature. The results indicate that most seeds of G. robertianum buried in sunny conditions germinate immediately after physical dormancy loss in summer. Seeds buried in shaded conditions also lose physical dormancy mainly during summer, but remain physiologically dormant and do not germinate until late winter or early spring. Besides physical dormancy, seeds of G. robertianum also initially have a high level of physiological dormancy, which is reduced during dry storage. Physiological dormancy is reduced through chilling in winter, thus enabling the seeds to germinate at low temperatures. We conclude that a complex combination of physical and physiological dormancy ensures that G. robertianum seeds germinate in summer at exposed sites and in early spring at shaded sites. PMID:20701699

Vandelook, F; Van Assche, J A

2010-09-01

157

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

PubMed

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. PMID:23448019

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

158

The evolution of seed dormancy: environmental cues, evolutionary hubs, and diversification of the seed plants.  

PubMed

Seed dormancy, by controlling the timing of germination, can strongly affect plant survival. The kind of seed dormancy, therefore, can influence both population and species-level processes such as colonization, adaptation, speciation, and extinction. We used a dataset comprising over 14,000 taxa in 318 families across the seed plants to test hypotheses on the evolution of different kinds of seed dormancy and their association with lineage diversification. We found morphophysiological dormancy to be the most likely ancestral state of seed plants, suggesting that physiologically regulated dormancy in response to environmental cues was present at the origin of seed plants. Additionally, we found that physiological dormancy (PD), once disassociated from morphological dormancy, acted as an 'evolutionary hub' from which other dormancy classes evolved, and that it was associated with higher rates of lineage diversification via higher speciation rates. The environmental sensitivity provided by dormancy in general, and by PD in particular, appears to be a key trait in the diversification of seed plants. PMID:24684268

Willis, Charles G; Baskin, Carol C; Baskin, Jerry M; Auld, Josh R; Venable, D Lawrence; Cavender-Bares, Jeannine; Donohue, Kathleen; Rubio de Casas, Rafael

2014-07-01

159

Mechanisms of disseminated cancer cell dormancy: an awakening field  

PubMed Central

Metastases arise from residual disseminated tumour cells (DTCs). This can happen years after primary tumour treatment because residual tumour cells can enter dormancy and evade therapies. As the biology of minimal residual disease seems to diverge from that of proliferative lesions, understanding the underpinnings of this new cancer biology is key to prevent metastasis. Analysis of approximately 7 years of literature reveals a growing focus on tumour and normal stem cell quiescence, extracellular and stromal microenvironments, autophagy and epigenetics as mechanisms that dictate tumour cell dormancy. In this Review, we attempt to integrate this information and highlight both the weaknesses and the strengths in the field to provide a framework to understand and target this crucial step in cancer progression. PMID:25118602

Sosa, María Soledad; Bragado, Paloma; Aguirre-Ghiso, Julio A.

2014-01-01

160

Dual effects of ethylene on potato dormancy and sprout growth.  

PubMed

Dormant potato tubers (Solanum tuberosum L.) of two cultivars were treated with various concentrations of ethylene gas for various exposure periods. As has been shown by others, ethylene caused a rapid but transient increase in respiration rate, which appeared to be independent of any effects on dormancy. All concentrations tested caused accelerated sprouting, 2 microliters per liter being the most effective. Ethylene exerts a dual effect on potato tubers: it markedly shortens the duration of rest, but it inhibits elongation of the sprouts during extended treatment. Comparing these results with published work on seeds, bulbs, and corms suggests that ethylene must have a significant but as yet unexplained role in rest and dormancy. However, since the most effective ethylene treatment did not equal the response elicited by treatment with ethylene chlorhydrin, other factors must also contribute to termination of rest. PMID:16658762

Rylski, I; Rappaport, L; Pratt, H K

1974-04-01

161

Virus Budding and the ESCRT Pathway  

PubMed Central

Enveloped viruses escape infected cells by budding through limiting membranes. In the decade since the discovery that the Human Immunodeficiency Virus (HIV) recruits cellular ESCRT (endosomal sorting complexes required for transport) machinery to facilitate viral budding, this pathway has emerged as the major escape route for enveloped viruses. In cells, the ESCRT pathway catalyzes the analogous membrane fission events required for the abscission stage of cytokinesis and for a series of “reverse topology” vesiculation events. Studies of enveloped virus budding are therefore providing insights into the complex cellular mechanisms of cell division and membrane protein trafficking (and vice versa). Here, we review how viruses mimic cellular recruiting signals to usurp the ESCRT pathway, discuss mechanistic models for ESCRT pathway functions, and highlight important research frontiers. PMID:24034610

Votteler, Jörg; Sundquist, Wesley I.

2013-01-01

162

Senescence, dormancy and tillering in perennial C4 grasses.  

PubMed

Perennial, temperate, C4 grasses, such as switchgrass and miscanthus have been tabbed as sources of herbaceous biomass for the production of green fuels and chemicals based on a number of positive agronomic traits. Although there is important literature on the management of these species for biomass production on marginal lands, numerous aspects of their biology are as yet unexplored at the molecular level. Perenniality, a key agronomic trait, is a function of plant dormancy and winter survival of the below-ground parts of the plants. These include the crowns, rhizomes and meristems that will produce tillers. Maintaining meristem viability is critical for the continued survival of the plants. Plant tillers emerge from the dormant crown and rhizome meristems at the start of the growing period in the spring, progress through a phase of vegetative growth, followed by flowering and eventually undergo senescence. There is nutrient mobilization from the aerial portions of the plant to the crowns and rhizomes during tiller senescence. Signals arising from the shoots and from the environment can be expected to be integrated as the plants enter into dormancy. Plant senescence and dormancy have been well studied in several dicot species and offer a potential framework to understand these processes in temperate C4 perennial grasses. The availability of latitudinally adapted populations for switchgrass presents an opportunity to dissect molecular mechanisms that can impact senescence, dormancy and winter survival. Given the large increase in genomic and other resources for switchgrass, it is anticipated that projected molecular studies with switchgrass will have a broader impact on related species. PMID:24467906

Sarath, Gautam; Baird, Lisa M; Mitchell, Robert B

2014-03-01

163

Human Granuloma In Vitro Model, for TB Dormancy and Resuscitation  

PubMed Central

Tuberculosis (TB) is responsible for death of nearly two million people in the world annually. Upon infection, Mycobacterium tuberculosis (Mtb) causes formation of granuloma where the pathogen goes into dormant state and can live for decades before resuscitation to develop active disease when the immune system of the host is weakened and/or suppressed. In an attempt to better understand host-pathogen interactions, several groups have been developing in vitro models of human tuberculosis granuloma. However, to date, an in vitro granuloma model in which Mtb goes into dormancy and can subsequently resuscitate under conditions that mimic weakening of the immune system has not been reported. We describe the development of a biomimetic in vitro model of human tuberculosis granuloma using human primary leukocytes, in which the Mtb exhibited characteristics of dormant mycobacteria as demonstrated by (1) loss of acid-fastness, (2) accumulation of lipid bodies (3) development of rifampicin-tolerance and (4) gene expression changes. Further, when these micro granulomas were treated with immunosuppressant anti-tumor necrosis factor-alpha monoclonal antibodies (anti-TNF? mAbs), resuscitation of Mtb was observed as has been found in humans. In this human in vitro granuloma model triacylglycerol synthase 1deletion mutant (?tgs1) with impaired ability to accumulate triacylglycerides (TG), but not the complemented mutant, could not go into dormancy. Deletion mutant of lipY, with compromised ability to mobilize the stored TG, but not the complemented mutant, was unable to come out of dormancy upon treatment with anti-TNF? mAbs. In conclusion, we have developed an in vitro human tuberculosis granuloma model that largely exhibits functional features of dormancy and resuscitation observed in human tuberculosis. PMID:23308269

Kapoor, Nidhi; Pawar, Santosh; Sirakova, Tatiana D.; Deb, Chirajyoti; Warren, William L.; Kolattukudy, Pappachan E.

2013-01-01

164

Interaction between bud-site selection and polarity-establishment machineries in budding yeast  

PubMed Central

Saccharomyces cerevisiae yeast cells polarize in order to form a single bud in each cell cycle. Distinct patterns of bud-site selection are observed in haploid and diploid cells. Genetic approaches have identified the molecular machinery responsible for positioning the bud site: during bud formation, specific locations are marked with immobile landmark proteins. In the next cell cycle, landmarks act through the Ras-family GTPase Rsr1 to promote local activation of the conserved Rho-family GTPase, Cdc42. Additional Cdc42 accumulates by positive feedback, creating a concentrated patch of GTP-Cdc42, which polarizes the cytoskeleton to promote bud emergence. Using time-lapse imaging and mathematical modelling, we examined the process of bud-site establishment. Imaging reveals unexpected effects of the bud-site-selection system on the dynamics of polarity establishment, raising new questions about how that system may operate. We found that polarity factors sometimes accumulate at more than one site among the landmark-specified locations, and we suggest that competition between clusters of polarity factors determines the final location of the Cdc42 cluster. Modelling indicated that temporally constant landmark-localized Rsr1 would weaken or block competition, yielding more than one polarity site. Instead, we suggest that polarity factors recruit Rsr1, effectively sequestering it from other locations and thereby terminating landmark activity. PMID:24062579

Wu, Chi-Fang; Savage, Natasha S.; Lew, Daniel J.

2013-01-01

165

Dormancy cues alter insect temperature-size relationships.  

PubMed

Developmental temperatures can have dramatic effects on body size in ectotherms. Thermal plasticity in body size is often viewed in the context of seasonality, but the role of seasonal dormancy responses in generating temperature-size relationships is underappreciated. We used the moth Helicoverpa zea (corn earworm) to examine how photoperiodic seasonal dormancy programming for pupal diapause affects the temperature-size relationship. Specifically, we partition out the contributions of somatic growth versus nutrient storage as fat to the thermal reaction norm for size. With increasing temperature from 16 °C to 20 °C, dormant pupae were both overall larger and progressively fatter than non-dormant pupae. This body mass response is likely driven by concurrent increases in food consumption and longer development times as temperatures increase. Our results demonstrate that seasonal photoperiodic cues can alter temperature-size relationships during pre-dormancy development. For biologists interested in seasonal effects on temperature-size relationships, our results suggest that the key to fully understanding these relationships may lie in integrating multiple seasonal cues and multiple aspects of body size and composition in a nutrient-allocation framework. PMID:25260999

Clemmensen, Sharon F; Hahn, Daniel A

2015-01-01

166

Regulation of Tumor Cell Dormancy by Tissue Microenvironments and Autophagy  

PubMed Central

The development of metastasis is the major cause of death in cancer patients. In certain instances, this occurs shortly after primary tumor detection and treatment, indicating these lesions were already expanding at the moment of diagnosis or initiated exponential growth shortly after. However, in many types of cancer, patients succumb to metastatic disease years and sometimes decades after being treated for a primary tumor. This has led to the notion that in these patients residual disease may remain in a dormant state. Tumor cell dormancy is a poorly understood phase of cancer progression and only recently have its underlying molecular mechanisms started to be revealed. Important questions that remain to be elucidated include not only which mechanisms prevent residual disease from proliferating but also which mechanisms critically maintain the long-term survival of these disseminated residual cells. Herein, we review recent evidence in support of genetic and epigenetic mechanisms driving dormancy. We also explore how therapy may cause the onset of dormancy in the surviving fraction of cells after treatment and how autophagy may be a mechanism that maintains the residual cells that are viable for prolonged periods. PMID:23143976

Sosa, Maria Soledad; Bragado, Paloma; Debnath, Jayanta

2013-01-01

167

Physical dormancy in seeds: a game of hide and seek?  

PubMed

Historically, 'physical dormancy', or 'hard seededness', where seeds are prevented from germinating by a water-impermeable seed coat, is viewed as a dormancy mechanism. However, upon water uptake, resumption of metabolism leads to the unavoidable release of volatile by-products, olfactory cues that are perceived by seed predators. Here, we examine the hypothesis that hard seeds are an anti-predator trait that evolved in response to powerful selection by small mammal seed predators. Seeds of two legume species with dimorphic seeds ('hard' and 'soft'), Robinia pseudoacacia and Vicia sativa, were offered to desert hamsters (Phodopus roborovskii) in a series of seed removal studies examining the differences in seed harvest between hard and soft seeds. Volatile compounds emitted by dry and imbibed soft seeds were identified by headspace gas chromatography-mass spectrometry (GC-MS). Fourteen main volatile compounds were identified, and hamsters readily detected both buried imbibed seeds and an artificial 'volatile cocktail' that mimicked the scent of imbibed seeds, but could not detect buried hard or dry soft seeds. We argue that physical dormancy has evolved to hide seeds from mammalian predators. This hypothesis also helps to explain some otherwise puzzling features of hard seeds and has implications for seed dispersal. PMID:23421728

Paulsen, Torbjørn Rage; Colville, Louise; Kranner, Ilse; Daws, Matthew I; Högstedt, Göran; Vandvik, Vigdis; Thompson, Ken

2013-04-01

168

View of east entrance to Flume Tunnel #2. In foreground, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of east entrance to Flume Tunnel #2. In foreground, covered decking (covered by debris) protects the flume below it (not visible). The extreme top of the tunnel entrance is visible in the middle of the picture, just beyond the covered decking. This is typical of gravity tunnel entrances and the only photograph representing these features in the system. Looking south - Childs-Irving Hydroelectric Project, Childs System, Flume Tunnel No. 2, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

169

Transient decreases in methylation at 5'-cCGG-3' sequences in potato (Solanum tuberosum L.) meristem DNA during progression of tubers through dormancy precede the resumption of sprout growth.  

PubMed

The 5-methylcytosine (5mC) content in DNA of tuber meristems isolated from field-grown potatoes (Solanum tuberosum L.) was determined during a 7-month storage period at 3 degrees C for three growing/postharvest seasons. No significant changes in 5mC levels were noted genome-wide or within 5'-CG-3' dinucleotide sequences, 5'-CG-3' islands or 5'-CA(T)G-3' trinucleotide sequences during storage. However, a consistent but transient 50-70% decrease in methylation at both cytosines within 5'-CCGG-3' sequences was detected that peaked 112-194 days after harvest. This result was corroborated by methylation-sensitive amplified fragment length polymorphism analysis of meristem DNA. Similar to tuber meristems undergoing progression through natural dormancy, premature chemical termination of dormancy resulted in rapid, transient 5'-CCGG-3' demethylation in meristem DNA. Minimum methylation levels at this sequence preceded initiation of high levels of de novo DNA synthesis by two days. Cytosine methylation status was also followed in in vitro-generated potato microtubers during 7 months of post-harvest storage. As in DNA from tuber bud meristems, no changes in genome-wide 5mC content or methylation at 5'-CA(T)G-3' or 5'-CG-3' island sequences were noted in microtuber DNA. However, there was a transient 46% drop in methylation at 5'-CG-3' dinucleotides concomitant with minimum levels of 5'-CCGG-3' methylation (30-60% below those in dormant microtubers) 57-98 days after harvest. As microtubers exited dormancy, there were sustained three- and seven-fold increases in RNA and DNA synthesis rates, peaking on or after 98 days of storage, respectively. Together, these data demonstrate that demethylation of 5'-CCGG-3' sequences occurs independently of tuber age during dormancy progression and precedes transcriptional activation of genes leading to cell division and meristem growth in potatoes. PMID:12602873

Law, R David; Suttle, Jeffrey C

2003-02-01

170

INTERIOR VIEW OF ENTRANCE TO LABORATORY, SHOWING HANDHAMMERED ALUMINUM DOORS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

INTERIOR VIEW OF ENTRANCE TO LABORATORY, SHOWING HAND-HAMMERED ALUMINUM DOORS AND MARBLE. NOTE ALUMINUM LIGHT FIXTURE - Alcoa Research Laboratory, Freeport Road, New Kensington, Westmoreland County, PA

171

View looking south from pavilion, showing south entrance house, south ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View looking south from pavilion, showing south entrance house, south wing, and engine house - Fairmount Waterworks, East bank of Schuylkill River, Aquarium Drive, Philadelphia, Philadelphia County, PA

172

12. VIEW LOOKING SOUTH FROM PAVILION, SHOWING SOUTH ENTRANCE HOUSE, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. VIEW LOOKING SOUTH FROM PAVILION, SHOWING SOUTH ENTRANCE HOUSE, SOUTH WING, AND ENGINE HOUSE - Fairmount Waterworks, East bank of Schuylkill River, Aquarium Drive, Philadelphia, Philadelphia County, PA

173

3. HISTORIC AMERICAN BUILDINGS SURVEY S. Lucas, Photographer, 1934 ENTRANCE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. HISTORIC AMERICAN BUILDINGS SURVEY S. Lucas, Photographer, 1934 ENTRANCE DETAIL. OFFICERS' QUARTERS. DETROIT ARSENAL. DEARBORN. MICHIGAN. - Detroit Arsenal, Officers' Quarters, 21950 Michigan Avenue, Dearborn, Wayne County, MI

174

Perspective view of east entrance from northeast National Home ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Perspective view of east entrance from northeast - National Home for Disabled Volunteer Soldiers, Pacific Branch, Mental Health Building, 11301 Wilshire Boulevard, West Los Angeles, Los Angeles County, CA

175

38. Typical elevated front entrance with wrought iron railings. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

38. Typical elevated front entrance with wrought iron railings. - Clark Howell Homes (Public Housing), Bounded by North Avenue, Lovejoy Street, Mills Street & Luckie Street, Atlanta, Fulton County, GA

176

?Cat FACE? SCAR ON LONGLEAF PINE TREE, OVERHILLS HISTORIC ENTRANCE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

?Cat FACE? SCAR ON LONGLEAF PINE TREE, OVERHILLS HISTORIC ENTRANCE ROAD, FACING NORTHEAST - Overhills, Fort Bragg Military Reservation, Approximately 15 miles NW of Fayetteville, Overhills, Harnett County, NC

177

7. INTERIOR, VIEW FROM ENTRANCE TOWARD ENCLOSED STAIRS AND REAR ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. INTERIOR, VIEW FROM ENTRANCE TOWARD ENCLOSED STAIRS AND REAR DOOR - Mulliken-Spragins Tenant House, National Museum of American History, Smithsonian Institution, Washington, District of Columbia, DC

178

Physical Dormancy in Seeds of the Holoparasitic Angiosperm Cuscuta australis (Convolvulaceae, Cuscuteae): Dormancy-breaking Requirements, Anatomy of the Water Gap and Sensitivity Cycling  

PubMed Central

Background and Aims Dormancy in seeds of Cuscuta (Convolvulaceae, tribe Cuscuteae) is due to a water-impermeable seed coat (physical dormancy). In nondormant seeds of several species of this family, bulges adjacent to the micropyle have been identified as the initial route of water entry into seeds (water gap). However, there are claims that water enters seeds of Cuscuta spp. via the entire seed coat. Although several studies have been done on seed coat anatomy of Cuscuta, none has identified and/or characterized the morphology/anatomy of a water gap. Thus, the primary aim of this research was to identify and describe the morphology and anatomy of the water gap in seeds of Cuscuta australis. It was also determined if sensitivity cycling to dormancy-breaking treatments occurs in seeds of this species. Methods Light microscopy, scanning electron microscopy, tissue-sectioning and dye-tracking and blocking experiments were used to investigate the morphology and anatomy of the water gap. Treatments simulating natural conditions were used to break seed dormancy. Storage of seeds at different temperatures was tested for their effect on sensitivity to dormancy-breaking treatment. Key Results Dormancy-breaking treatments caused the tightly closed hilar fissure to open. Staining was observed in cells below the hilum area but not in those below the seed coat away from the hilum. Sensitivity to dormancy-breaking treatment was induced by storing seeds dry and reduced by storing them wet. Conclusions Whereas bulges adjacent to the micropyle act as the water gap in other species of Convolvulaceae with physical dormancy, the hilar fissure serves this function in Cuscuta. Cuscuta australis can cycle between insensitivity ? sensitivity to dormancy-breaking treatments. PMID:18453546

Jayasuriya, K. M. G. Gehan; Baskin, Jerry M.; Geneve, Robert L.; Baskin, Carol C.; Chien, Ching-Te

2008-01-01

179

Involvement of endogenous gibberellins in potato tuber dormancy and early sprout growth: a critical assessment.  

PubMed

The role of endogenous gibberellins (GAs) in the regulation of potato (Solanum tuberosum) tuber dormancy was examined by determining: 1. changes in endogenous GA levels during natural dormancy progression, 2. the effects of GA biosynthesis inhibitors on tuber dormancy duration and 3. the dormancy status and tuber GA levels in a dwarf mutant of potato. The tubers (cv. Russet Burbank) used in these studies were still completely dormant after 98 days of storage. Between 98 and 134 days of storage, dormancy began to end and tubers exhibited limited (< 2 mm) sprout growth. Tuber dormancy weakened with further storage and tubers exhibited greater rates of sprout growth after 187 days of storage. Tubers stored for 212 days or longer were completely non-dormant and exhibited vigorous sprout growth. Immediately after harvest, the endogenous contents of GA19, GA20, and GA1 were relatively high (0.48-0.62 ng g fresh weight(-1)). The content of these GAs declined between 33 and 93 days of storage. Internal levels of GA19, GA20, and GA, rose slightly between 93 and 135 days of storage reaching levels comparable to those found in highly dormant tubers immediately after harvest. Levels of GA19, GA20, and GA1 continued to increase as sprout growth became more vigorous. Neither GA4 nor GA8 was detected in any tuber sample regardless of dormancy status. Dormant tubers exhibited a time-dependent increase in apparent GA sensitivity. Freshly harvested tubers were completely insensitive to exogenous GAs. As postharvest storage continued, exogenous GAs promoted premature dormancy release with GA1 and GA20 eliciting the greatest response. Injection of up to 5 microg tuber(-1) of kaurene, GA12, GA19 or GA8 had no effect on dormancy release. Sprout growth from non-dormant tubers was also promoted by exogenous GA in the following sequence of activity: GA1 = GA20 > GA19. Kaurene, GA12, and GA8 were inactive. Continuous exposure of developing tubers to inhibitors of GA biosynthesis (AMO-1618, ancymidol, or tetcyclasis) did not extend tuber dormancy but rather hastened dormancy release. Comparison of tuber dormancy and GA1 content in tubers of a wild-type and dwarf mutant of S. tuberosum ssp. andigena revealed a near-identical pattern of dormancy progression in spite of the absence of detectable levels of GA1 in tubers of the dwarf sibling at any time during dormancy progression. Collectively, these results do not support a role for endogenous GA in potato tuber dormancy release but are consistent with a role for GAs in the regulation of subsequent sprout growth. PMID:15022829

Suttle, Jeffrey C

2004-02-01

180

Ecotypic variation of summer dormancy relaxation associated with rainfall gradient in the geophytic grass Poa bulbosa  

PubMed Central

Background and Aims Summer dormancy is an adaptive trait in geophytes inhabiting regions with a Mediterranean climate, allowing their survival through the hot and dry summers. Summer dormancy in Poa bulbosa is induced by increasing day-length and temperature and decreasing water availability during spring. Populations from arid habitats became dormant earlier than those from mesic habitats. Relaxation of dormancy was promoted by the hot, dry summer conditions. Here we test the hypothesis that dormancy relaxation is also delayed in ecotypes of P. bulbosa inhabiting arid regions, as a cautious strategy related to the greater unpredictability of autumn rains associated with decreasing precipitation. Methods Ecotypes collected across a precipitation gradient (100–1200 mm year?1) in the Mediterranean climate region were grown under similar conditions in a net-house in Israel. Differences among ecotypes in dormancy induction and dormancy relaxation were determined by measuring time to dormancy onset in spring, and time to sprouting after the first effective rain in autumn. Seasonal and ecotype variation in dormancy relaxation were assessed by measuring time to sprouting initiation, rate of sprouting and maximal sprouting of resting dry bulbs sampled in the net-house during late spring, and mid- and late summer, and planted in a wet substrate at temperatures promoting (10 °C) or limiting (20 °C) sprouting. Key Results Earlier dormancy in the spring and delayed sprouting in autumn were correlated with decreasing mean annual rainfall at the site of ecotype origin. Seasonal and ecotype differences in dormancy relaxation were expressed in bulbs planted at 20 °C. During the summer, time to sprouting decreased while rate of sprouting and maximal sprouting increased, indicating dormancy relaxation. Ecotypes from more arid sites across the rainfall gradient showed delayed onset of sprouting and lower maximal sprouting, but did not differ in rate of sprouting. Planting at 10 °C promoted sprouting and cancelled differences among ecotypes in dormancy relaxation. Conclusions Both the induction and the relaxation of summer dormancy in P. bulbosa are correlated with mean annual precipitation at the site of population origin. Ecotypes from arid habitats have earlier dormancy induction and delayed dormancy relaxation, compared with those from mesic habitats. PMID:20156924

Ofir, Micha; Kigel, Jaime

2010-01-01

181

Regulation of Summer Dormancy by Water Deficit and ABA in Poa bulbosa Ecotypes  

PubMed Central

Background and Aims Survival of many herbaceous species in Mediterranean habitats during the dry, hot summer depends on the induction of summer dormancy by changes in environmental conditions during the transition between the winter (growth) season to the summer (resting) season, i.e. longer days, increasing temperature and drought. In Poa bulbosa, a perennial geophytic grass, summer dormancy is induced by long days, and the induction is enhanced by high temperature. Here the induction of summer dormancy in a Mediterranean perennial grass by water deficit under non-inductive photoperiodic conditions is reported for the first time. Methods Plants grown under 22/16 °C and non-inductive short-day (9 h, SD) were subjected to water deficit (WD), applied as cycles of reduced irrigation, or sprayed with ABA solutions. They were compared with plants in which dormancy was induced by transfer from SD to inductive long-day (16 h, LD). Responses of two contrasting ecotypes, from arid and mesic habitats were compared. Dormancy relaxation in bulbs from these ecotypes and treatments was studied by comparing sprouting capacity in a wet substrate at 10 °C of freshly harvested bulbs to that of dry-stored bulbs at 40 °C. Endogenous ABA in the bulbs was determined by monoclonal immunoassay analysis. Key Results Dormancy was induced by WD and by ABA application in plants growing under non-inductive SD. Dormancy induction by WD was associated with increased levels of ABA. Bulbs were initially deeply dormant and their sprouting capacity was very low, as in plants in which dormancy was induced by LD. Dormancy was released after 2 months dry storage at 40 °C in all treatments. ABA levels were not affected by dormancy relaxation. Conclusions Summer dormancy in P. bulbosa can be induced by two alternative and probably additive pathways: (1) photoperiodic induction by long-days, and (2) water deficit. Increased levels of endogenous ABA are involved in both pathways. PMID:17202183

Ofir, Micha; Kigel, Jaime

2007-01-01

182

Tube entrance heat transfer with deposit formation  

NASA Technical Reports Server (NTRS)

A two-peak wall temperature profile was observed while flowing a kerosene-type gas turbine fuel through a direct-resistance heated tube at an entrance Reynolds number of about 1500. The downstream peak gradually diminished as deposits formed inside the tube, and only one peak remained after seven hours. The observation is explained qualitatively on the basis of analytical and experimental results reported in the literature. It is shown that the temperature profile can be divided into five regions: development of the thermal boundary layer, appearance of the secondary flows, fully developed thermal boundary layer, transition to turbulent flow, and turbulent flow. Deposits increase the tube roughness and reduce the length required for laminar-turbulent transition.

Szetela, E. J.; Sobel, D. R.

1982-01-01

183

Cryopreservation of Salix sp. dormant winter buds  

Technology Transfer Automated Retrieval System (TEKTRAN)

In cryopreservation, using dormant winter buds (DB) as source plant materials is economically advantageous over tissue culture options (TC). Processing DB does not require aseptic conditions and elaborate cryopreservation procedures. However, the DB approach is only feasible for cryopreserving a sel...

184

Bilingual Buds: The Evolution of a Program  

ERIC Educational Resources Information Center

The impetus to begin Bilingual Buds came about six years ago when the author, pregnant with twins and commuting into New York City, was reading about the numerous cognitive benefits for children of acquiring a second language early in their lives. She was surprised to learn that even by the age of six months, children begin to lose the ability to…

Huang, Sharon

2009-01-01

185

The dormant buds of Rhabdopleura compacta (Hemichordata)  

Microsoft Academic Search

Rhabdopleura has an overwintering stage that consists of two layers of cells surrounding a central yolk mass. This cellular part is surrounded by a thick electron dense capsule which is secreted by the bud itself. The capsule is probably impervious and protective to its contents.

P. N. Dilly

1975-01-01

186

Dormant bud preservation for germplasm conservation  

Technology Transfer Automated Retrieval System (TEKTRAN)

The suitability of dormant buds (DB) for cryopreservation of different plant species has been demonstrated in several reports. For the majority of the species, processing DB for long-term liquid nitrogen storage does not involve establishing tissue cultures and the time for growing out post-cryo mat...

187

The role of temperature in the regulation of dormancy and germination of two related summer-annual mudflat species  

Microsoft Academic Search

Dormancy and germination requirements were investigated in seeds (achenes) of the closely-related annuals Bidens cernua and Bidens tripartita (Asteraceae). They showed clear differences in their temperature requirements for germination, their dormancy and seed longevity in soil. In B. cernua seeds, primary dormancy was relieved when stratified at 3, 8, and 12°C, as seeds germinated to a maximum of more than

Markus Brändel

2004-01-01

188

b-1,3-Glucanase gene expression in low-hydrated seeds as a mechanism for dormancy release during tobacco  

E-print Network

b-1,3-Glucanase gene expression in low-hydrated seeds as a mechanism for dormancy release during-imposed dormancy of tobacco (Nicotiana tabacum). After-ripening and over-expression of class I b-1,3-glucanase (b-ripening. Keywords: after-ripening, coat-imposed dormancy, b-1,3-glucanase, gene expression, low-hydrated state, seed

Leubner, Gerhard

189

Forecasting emergence and movement of overwintering hazelnut big bud mites from big buds  

Microsoft Academic Search

Eriophyoid big bud mites are key pests of hazelnut throughout the world, but they are difficult to control with chemicals\\u000a or other methods because they are protected inside the bud. The most effective time for control is during the relatively short\\u000a emergence period which is difficult for growers to predict. The key objectives of this study were to monitor mite

Janette Webber; R. Bruce Chapman; S. P. Worner

2008-01-01

190

Hydrothermal time analysis of seed dormancy in true (botanical) potato seeds  

E-print Network

to water potential (C) and temperature (T) can describe these features of seed behaviour. We used) of TPS for 7 or 30 days partially or fully alleviated primary dormancy. The median base water potential model, temperature, water potential Introduction Dormancy is the lack of the capacity for a seed `to

Bradford, Kent

191

Ethylene Is Not Involved in Hormone- and Bromoethane-Induced Dormancy Break in Russet Burbank Minitubers  

Technology Transfer Automated Retrieval System (TEKTRAN)

The involvement of ethylene in the dormancy breaking actions of cytokinins, GA, and BE was investigated using Russet Burbank minitubers. Injection of 10µg tuber-1 BA, CP, GA, NG, or ZEA or 24 hour exposure to BE effectively broke dormancy and stimulated sprout growth over a two-week period. Althou...

192

Opposite Effects of Daylength and Temperature on Flowering and Summer Dormancy of Poa bulbosa  

Microsoft Academic Search

? Background and Aims The timing of flowering and summer dormancy induction plays a central role in the adaptation of Mediterranean geophytes to changes in the length of the growth season along rainfall gradients. Our aim was to analyse the role of the variation in the responses of flowering and summer dormancy to vernalization, daylength and growth temperature for the

MICHA OFIR; JAIME KIGEL

2006-01-01

193

Opposite Effects of Daylength and Temperature on Flowering and Summer Dormancy of Poa bulbosa  

Microsoft Academic Search

? Background and Aims The timing of flowering and summer dormancy induction plays a central role in the adaptation of Mediterranean geophytes to changes in the length of the growth season along rainfall gradients. Our aim was to analyse the role of the variation in the responses of flowering and summer dormancy to vernalization, daylength and growth temperature for the

MICHA O FIR; J AIME K IGEL

194

Dormancy and germination of six Rhinanthus species in relation to climate  

Microsoft Academic Search

The genus Rhinanthus (Orobanchaceae) consists of annual hemiparasites that occur in a wide range of climates. Patterns of dormancy and germination were studied for six species sampled in areas ranging from the Pyrenees to Northern Scandinavia, and from sea level up to about 2500 m altitude in the Alpine region. Dormancy was broken by a 2 to 6 months period

Borg ter S. J

2005-01-01

195

15. Front security entrance to the perimeter acquisition radar building, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. Front security entrance to the perimeter acquisition radar building, showing rotogates 1 and 2 and entrance door to security operations control center (SOCC), room #108 - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

196

7. CLOSEUP VIEW OF ENTRANCE TO BUILDING NO. 33 FACING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. CLOSE-UP VIEW OF ENTRANCE TO BUILDING NO. 33 FACING EAST. VIEW SHOWS CONCRETE PLANTING BOXES ON EACH SIDE OF ENTRANCE AND CONCRETE CANOPY OVERHANG ABOVE. - U.S. Naval Base, Pearl Harbor, Marine Barracks, West Loch, B Avenue near Arizona Road, Pearl City, Honolulu County, HI

197

6. CLOSEUP VIEW OF ENTRANCE TO BUILDING NO. 33 AT ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. CLOSE-UP VIEW OF ENTRANCE TO BUILDING NO. 33 AT KITCHEN WING FACING NORTH. VIEW SHOWS CONCRETE CANOPY OVERHANG ABOVE ENTRANCE. - U.S. Naval Base, Pearl Harbor, Marine Barracks, West Loch, B Avenue near Arizona Road, Pearl City, Honolulu County, HI

198

Chemically forced dormancy termination mimics natural dormancy progression in potato tuber meristems by reducing ABA content and modifying expression of genes involved in regulating ABA synthesis and metabolism.  

PubMed

The length of potato tuber dormancy depends on both the genotype and the environmental conditions during growth and storage. Abscisic acid (ABA) has been shown to play a critical role in tuber dormancy control but the mechanisms regulating ABA content during dormancy, as well as the sites of ABA synthesis, and catabolism are unknown. Recently, a temporal correlation between changes in ABA content and certain ABA biosynthetic and catabolic genes has been reported in stored field tubers during physiological dormancy progression. However, the protracted length of natural dormancy progression complicated interpretation of these data. To address this issue, in this study the synthetic dormancy-terminating agent bromoethane (BE) was used to induce rapid and highly synchronous sprouting of dormant tubers. The endogenous ABA content of tuber meristems increased 2-fold 24 h after BE treatment and then declined dramatically. By 7 d post-treatment, meristem ABA content had declined by >80%. Exogenous [(3)H]ABA was readily metabolized by isolated meristems to phaseic and dihydrophaseic acids. BE treatment resulted in an almost 2-fold increase in the rate of ABA metabolism. A differential expression of both the StNCED and StCYP707A gene family members in meristems of BE-treated tubers is consistent with a regulatory role for StNCED2 and the StCYP707A1 and StCYP707A2 genes. The present results show that the changes in ABA content observed during tuber dormancy progression are the result of a dynamic equilibrium of ABA biosynthesis and degradation that increasingly favours catabolism as dormancy progresses. PMID:16831846

Destefano-Beltrán, Luis; Knauber, Donna; Huckle, Linda; Suttle, Jeffrey

2006-01-01

199

Tanned or Burned: The Role of Fire in Shaping Physical Seed Dormancy  

PubMed Central

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. PMID:23227267

Moreira, Bruno; Pausas, Juli G.

2012-01-01

200

REDUCED DORMANCY5 Encodes a Protein Phosphatase 2C That Is Required for Seed Dormancy in Arabidopsis[C][W][OPEN  

PubMed Central

Seed dormancy determines germination timing and contributes to crop production and the adaptation of natural populations to their environment. Our knowledge about its regulation is limited. In a mutagenesis screen of a highly dormant Arabidopsis thaliana line, the reduced dormancy5 (rdo5) mutant was isolated based on its strongly reduced seed dormancy. Cloning of RDO5 showed that it encodes a PP2C phosphatase. Several PP2C phosphatases belonging to clade A are involved in abscisic acid signaling and control seed dormancy. However, RDO5 does not cluster with clade A phosphatases, and abscisic acid levels and sensitivity are unaltered in the rdo5 mutant. RDO5 transcript could only be detected in seeds and was most abundant in dry seeds. RDO5 was found in cells throughout the embryo and is located in the nucleus. A transcriptome analysis revealed that several genes belonging to the conserved PUF family of RNA binding proteins, in particular Arabidopsis PUMILIO9 (APUM9) and APUM11, showed strongly enhanced transcript levels in rdo5 during seed imbibition. Further transgenic analyses indicated that APUM9 reduces seed dormancy. Interestingly, reduction of APUM transcripts by RNA interference complemented the reduced dormancy phenotype of rdo5, indicating that RDO5 functions by suppressing APUM transcript levels. PMID:25415980

Xiang, Yong; Nakabayashi, Kazumi; Ding, Jia; He, Fei; Bentsink, Leónie; Soppe, Wim J.J.

2014-01-01

201

Wheat ABA-insensitive mutants result in reduced grain dormancy.  

PubMed

This paper describes the isolation of wheat mutants in the hard red spring Scarlet resulting in reduced sensitivity to the plant hormone abscisic acid (ABA) during seed germination. ABA induces seed dormancy during embryo maturation and inhibits the germination of mature seeds. Wheat sensitivity to ABA gradually decreases with dry after-ripening. Scarlet grain normally fails to germinate when fully dormant, shows ABA sensitive germination when partially after-ripened, and becomes ABA insensitive when after-ripened for 8-12 months. Scarlet ABA-insensitive (ScABI) mutants were isolated based on the ability to germinate on 5 µM ABA after only 3 weeks of after-ripening, a condition under which Scarlet would fail to germinate. Six independent seed-specific mutants were recovered. ScABI 1, ScABI2, ScABI3 and ScABI4 are able to germinate more efficiently than Scarlet at up to 25 µM ABA. The two strongest ABA insensitive lines, ScABI3 and ScABI4, both proved to be partly dominant suggesting that they result from gain-of-function mutations. The ScABI1, ScABI2, ScABI3, ScABI4, and ScABI5 mutants after-ripen more rapidly than Scarlet. Thus, ABA insensi-tivity is associated with decreased grain dormancy in Scarlet wheat. This suggests that ABA sensitivity is an important factor controlling grain dormancy in wheat, a trait that impacts seedling emergence and pre-harvest sprouting resistance. PMID:25431501

Schramm, Elizabeth C; Nelson, Sven K; Steber, Camille M

2012-03-31

202

Short Photoperiod Induces Dormancy in Lotus (Nelumbo nucifera)  

PubMed Central

• Background and Aims Lotus (Nelumbo nucifera) has been cultivated as an ornamental and food plant in Japan for more than 1000 years. As large areas are required for its cultivation (approximately 2?m2 per plant), physiological research, such as into the effect of environmental factors on dormancy, has not been well studied until recently. In this paper, seedlings were used to examine environmental factors affecting dormancy induction. • Methods In a first experiment, seeds were sown from 6 April to 6 October at 2-month intervals, and cultivated for 2 months in an unheated greenhouse. In a second experiment, seeds were prepared for germination on 16 November and 16 May and the seedlings were grown at 25 or 30?°C under natural daylength in phytotron growth rooms. After 1 month, the seedlings were cultivated at 20, 25 or 30?°C for a further month. The number of leaves and rhizome branches on the main stem were counted, and growth of rhizomes on the main stem was calculated using a rhizome enlargement index (= maximum internode diameter/internode length) after 2 months of culture in both experiments. • Key Results Rhizomes elongated without enlargement when the seeds were sown in April and June. Sowing the seeds in August and October resulted in rhizome enlargement from the tenth and fifth internodes, respectively. Rhizomes enlarged in the November-sowing but elongated in the May-sowing irrespective of temperature treatments under natural daylength in the phytotron rooms. The seedlings cultivated from May at 25–30?°C for 2 months had more leaves, and more rhizome branches and nodes than those cultivated from November. • Conclusions Short days led to induced dormancy in lotus. PMID:16287906

MASUDA, JUN-ICHIRO; URAKAWA, TOSHIHIRO; OZAKI, YUKIO; OKUBO, HIROSHI

2006-01-01

203

Microbial dormancy improves development and experimental validation of ecosystem model.  

PubMed

Climate feedbacks from soils can result from environmental change followed by response of plant and microbial communities, and/or associated changes in nutrient cycling. Explicit consideration of microbial life-history traits and functions may be necessary to predict climate feedbacks owing to changes in the physiology and community composition of microbes and their associated effect on carbon cycling. Here we developed the microbial enzyme-mediated decomposition (MEND) model by incorporating microbial dormancy and the ability to track multiple isotopes of carbon. We tested two versions of MEND, that is, MEND with dormancy (MEND) and MEND without dormancy (MEND_wod), against long-term (270 days) carbon decomposition data from laboratory incubations of four soils with isotopically labeled substrates. MEND_wod adequately fitted multiple observations (total C-CO2 and (14)C-CO2 respiration, and dissolved organic carbon), but at the cost of significantly underestimating the total microbial biomass. MEND improved estimates of microbial biomass by 20-71% over MEND_wod. We also quantified uncertainties in parameters and model simulations using the Critical Objective Function Index method, which is based on a global stochastic optimization algorithm, as well as model complexity and observational data availability. Together our model extrapolations of the incubation study show that long-term soil incubations with experimental data for multiple carbon pools are conducive to estimate both decomposition and microbial parameters. These efforts should provide essential support to future field- and global-scale simulations, and enable more confident predictions of feedbacks between environmental change and carbon cycling. PMID:25012899

Wang, Gangsheng; Jagadamma, Sindhu; Mayes, Melanie A; Schadt, Christopher W; Megan Steinweg, J; Gu, Lianhong; Post, Wilfred M

2015-01-01

204

Bud3 activates Cdc42 to establish a proper growth site in budding yeast  

PubMed Central

Cell polarization occurs along a single axis that is generally determined by a spatial cue, yet the underlying mechanism is poorly understood. Using biochemical assays and live-cell imaging, we show that cell polarization to a proper growth site requires activation of Cdc42 by Bud3 in haploid budding yeast. Bud3 catalyzes the release of guanosine diphosphate (GDP) from Cdc42 and elevates intracellular Cdc42–guanosine triphosphate (GTP) levels in cells with inactive Cdc24, which has as of yet been the sole GDP–GTP exchange factor for Cdc42. Cdc42 is activated in two temporal steps in the G1 phase: the first depends on Bud3, whereas subsequent activation depends on Cdc24. Mutational analyses suggest that biphasic activation of Cdc42 in G1 is necessary for assembly of a proper bud site. Biphasic activation of Cdc42 or Rac GTPases may be a general mechanism for spatial cue–directed cell polarization in eukaryotes. PMID:25002677

Kang, Pil Jung; Lee, Mid Eum

2014-01-01

205

Co-adaptation of seed dormancy and flowering time in the arable weed Capsella bursa-pastoris (shepherd's purse)  

PubMed Central

Background and Aims The duration of the plant life cycle is an important attribute that determines fitness and coexistence of weeds in arable fields. It depends on the timing of two key life-history traits: time from seed dispersal to germination and time from germination to flowering. These traits are components of the time to reproduction. Dormancy results in reduced and delayed germination, thus increasing time to reproduction. Genotypes in the arable seedbank predominantly have short time to flowering. Synergy between reduced seed dormancy and reduced flowering time would create stronger contrasts between genotypes, offering greater adaptation in-field. Therefore, we studied differences in seed dormancy between in-field flowering time genotypes of shepherd's purse. Methods Genotypes with early, intermediate or late flowering time were grown in a glasshouse to provide seed stock for germination tests. Secondary dormancy was assessed by comparing germination before and after dark-incubation. Dormancy was characterized separately for seed myxospermy heteromorphs, observed in each genotype. Seed carbon and nitrogen content and seed mass were determined as indicators of seed filling and resource partitioning associated with dormancy. Key Results Although no differences were observed in primary dormancy, secondary dormancy was weaker among the seeds of early-flowering genotypes. On average, myxospermous seeds showed stronger secondary dormancy than non-myxospermous seeds in all genotypes. Seed filling was similar between the genotypes, but nitrogen partitioning was higher in early-flowering genotypes and in non-myxospermous seeds. Conclusions In shepherd's purse, early flowering and reduced seed dormancy coincide and appear to be linked. The seed heteromorphism contributes to variation in dormancy. Three functional groups of seed dormancy were identified, varying in dormancy depth and nitrate response. One of these groups (FG-III) was distinct for early-flowering genotypes. The weaker secondary dormancy of early-flowering genotypes confers a selective advantage in arable fields. PMID:22147546

Toorop, Peter E.; Campos Cuerva, Rafael; Begg, Graham S.; Locardi, Bruna; Squire, Geoff R.; Iannetta, Pietro P. M.

2012-01-01

206

The relativistic titls of Giza pyramids' entrance-passages  

NASA Astrophysics Data System (ADS)

The tilts of Giza pyramids' entrance-passages have never been considered as if they were the result of relativistic mathematical equations, and never been thought to encode the Earth's obliquity parameters. This paper presents an attempt to retrieve the method of establishing the equations that the pyramids' designer used to quantify the entrance-passages' tilts of these architectonic masterpieces. It proves that the pyramids' designer was able to include the geographic, astronomical and time parameters in one relativistic equation, encoding the date of the design of the Giza pyramids in the tilt of the entrance passage of the great pyramid.

Aboulfotouh, H.

207

Temperature rather than photoperiod controls growth cessation and dormancy in Sorbus species  

PubMed Central

Environmental regulation of growth and dormancy of four Sorbus genotypes was studied in controlled environments. Emphasis was placed on assessment of the presence and nature of the deficient photoperiodic dormancy regulation system that has previously been reported for some woody Rosaceae species. Two genotypes of Sorbus aucuparia L. maintained indeterminate growth for 8 weeks and 9 weeks at temperatures of 15 °C and 21 °C in both 20 h and 10 h photoperiods, while at 9 °C, in the same photoperiodic conditions, they immediately ceased growing. At the higher temperatures, initiation of new leaves (nodes) was unaffected by photoperiod, while internode elongation was significantly enhanced by long days (LD). However, even after prolonged exposure to 9 °C, most plants resumed growth when moved to high temperature and LD, indicating a shallow state of dormancy. Seedlings of Sorbus intermedia (J. F. Ehrh.) Pers. and micro-propagated plantlets of S. commixta Hedl. ‘Dodong’ were also unaffected by photoperiod during primary growth, but failed to elongate and gradually became dormant regardless of temperature and day-length conditions. However, after chilling and breaking of dormancy, the plants elongated vigorously but changed to a determinate mode of growth. Furthermore, a temperature of 9 °C was found to be fully effective for breaking dormancy in S. intermedia plants. It is concluded that deficient photoperiodic dormancy control seems widespread in the Rosaceae and that, in such plants, both dormancy induction and release is brought about by low temperature. The potential impacts of climate change on such trees are discussed. PMID:21862485

Heide, Ola M.

2011-01-01

208

Dependency of seed dormancy types on embryo traits and environmental conditions in Ribes species.  

PubMed

The hypothesis that seed dormancy may be dependent on environmental conditions and seed morphological traits was tested for six Ribes species, across an altitudinal gradient of 1300 m and a longitudinal separation of 120°. Embryo measurements and seed germination experiments were conducted for R. alpinum L., R. hudsonianum Richardson var. petiolare (Douglas) Jancz., R. nevadaense Kellogg, R. roezlii Regel var. cruentum (Greene) Rehder and R. speciosum Pursh, and data taken from the literature for R. multiflorum Kit. ex Schult. ssp. sandalioticum Arrigoni. Germination was compared with seed viability to reveal proportional seed dormancy, which was then correlated to seed/embryo morphological traits and these traits related to the seed provenance environment. The embryos of all the investigated species are linear underdeveloped and all had a morphological component of seed dormancy (MD). Seeds of R. roezlii, R. hudsonianum and R. nevadaense required a temperature and/or hormone pre-treatment in order to germinate, highlighting morphophysiological seed dormancy (MPD). Seed dormancy was found to be strongly negatively correlated with embryo length, but not with embryo to seed (E:S) ratio or seed mass. Initial embryo length was positively related to mean annual temperature. Seed dormancy in the investigated Ribes species could be quantified and predicted by the interaction of embryo traits and environmental conditions. This approach may be helpful in assessing and predicting seed dormancy in the Ribes genus and in other genera and families with underdeveloped embryos. PMID:24138146

Mattana, E; Stuppy, W H; Fraser, R; Waller, J; Pritchard, H W

2014-07-01

209

Temperature rather than photoperiod controls growth cessation and dormancy in Sorbus species.  

PubMed

Environmental regulation of growth and dormancy of four Sorbus genotypes was studied in controlled environments. Emphasis was placed on assessment of the presence and nature of the deficient photoperiodic dormancy regulation system that has previously been reported for some woody Rosaceae species. Two genotypes of Sorbus aucuparia L. maintained indeterminate growth for 8 weeks and 9 weeks at temperatures of 15 °C and 21 °C in both 20 h and 10 h photoperiods, while at 9 °C, in the same photoperiodic conditions, they immediately ceased growing. At the higher temperatures, initiation of new leaves (nodes) was unaffected by photoperiod, while internode elongation was significantly enhanced by long days (LD). However, even after prolonged exposure to 9 °C, most plants resumed growth when moved to high temperature and LD, indicating a shallow state of dormancy. Seedlings of Sorbus intermedia (J. F. Ehrh.) Pers. and micro-propagated plantlets of S. commixta Hedl. 'Dodong' were also unaffected by photoperiod during primary growth, but failed to elongate and gradually became dormant regardless of temperature and day-length conditions. However, after chilling and breaking of dormancy, the plants elongated vigorously but changed to a determinate mode of growth. Furthermore, a temperature of 9 °C was found to be fully effective for breaking dormancy in S. intermedia plants. It is concluded that deficient photoperiodic dormancy control seems widespread in the Rosaceae and that, in such plants, both dormancy induction and release is brought about by low temperature. The potential impacts of climate change on such trees are discussed. PMID:21862485

Heide, Ola M

2011-11-01

210

Dormancy, germination, emergence and ecology of Gardner saltbush (Atriplex gardneri (Moq. ) D. Dietr. ) seeds  

SciTech Connect

Gardner saltbush (Atriplex gardneri (Moq.) D. Dietr.) provides valuable winter browse and is an important soil stabilizer in arid, alkaline, and saline areas of the intermountain region. However, seed dormancy and poor seedling vigor inhibit its potential for revegetation by direct seeding on disturbed lands. The objectives of this study were to 1) develop seed treatments which would overcome dormancy in Gardner saltbush seeds, 2) evaluate field establishment by direct seeding of Gardner saltbush, and 3) characterize seed dormancy, seedling vigor and some aspects of the ecology of germination in Gardner saltbush. In the laboratory, single and combined pretreatments removed dormancy to varying degrees. Dormancy was completely alleviated with 15 months dry after-ripening + scarification + 24 hours washing + 4 weeks stratification. Dry after-ripening and scarification appeared to facilitate effects of washing and stratification. Physiologically, indirect evidence was obtained suggesting both embryo and seedcoat mediated dormancy occur in Gardner saltbush. Ecologically, the various levels of germination response to simulated environmental pretreatments appeared to be an adaptation of Gardner saltbush seeds to ensure a temporal dispersal of release from dormancy. This increases the probability that under natural conditions some seedlings will emerge during times when the environment is amenable to seedling survival.

Ansley, R.J. Jr.

1983-01-01

211

Identification of differentially expressed genes in potato associated with tuber dormancy release.  

PubMed

Potato (Solanum tuberosum L.) tuber dormancy and sprouting is very important to potato cultivation and processing. In the present experiment, suppression subtractive hybridization was employed to identify differentially expressed genes in potato associated with tuber dormancy release. 576 random clones were selected from subtractive library and successfully sequenced. A total of 304 effective expressed sequence tags (ESTs) were obtained ultimately. The ESTs have been deposited in the EMBL\\GenBank\\DDBJ nucleotide sequence data libraries under accession numbers from JK483901 to JK484204. GO annotation showed that 45, 34 and 3 % ESTs were associated with binding, catalytic activity and signaling respectively, some of which were confirmed to be involved in plant dormancy breaking, however, 14 % of the ESTs did not show significant homology to any database proteins. A real-time quantitative PCR (RT-qPCR) analysis of the expression patterns of 14 selectable transcripts showed that 13 selected candidate genes were significantly up-regulated in the development process of tuber from dormancy to sprouting. A full length cDNA of ADP-ribosylation factor (ARF) gene was cloned and found it belonged to potato ARF1 gene. Tissue specific expression analysis showed ARF1 expression level was the highest in tuber. RT-qPCR analysis of the expression profile of ARF1 gene from potato tuber dormancy to sprouting revealed that the ARF1 gene expression was significantly increased after tuber dormancy breaking, which suggested that it probably associated with tuber dormancy and sprouting. PMID:23065212

Liu, Bailin; Zhang, Ning; Wen, Yikai; Si, Huaijun; Wang, Di

2012-12-01

212

Role of Endogenous Abscisic Acid in Potato Microtuber Dormancy.  

PubMed

Potato (Solanum tuberosum L. cv Russet Burbank) microtubers generated in vitro from single-node explants contained substantial amounts (approximately 250 pmol/g fresh weight) of free abscisic acid (ABA) and were completely dormant for a minimum of 12 weeks. Microtubers that developed in the presence of 10 [mu]M fluridone (FLD) contained considerably reduced amounts (approximately 5-25 pmol/g fresh weight) of free ABA and exhibited a precocious loss of dormancy. Inclusion of exogenous racemic ABA in the FLD-containing medium suppressed the premature sprouting of these microtubers in a dose-dependent manner. At a concentration of 50 [mu]M, exogenous ABA restored internal ABA levels to control values and completely inhibited FLD-induced precocious sprouting. Exogenous jasmonic acid was ineffective in suppressing FLD-induced sprouting. Application of FLD to preformed, fully dormant microtubers also resulted in a reduction in internal ABA content and precocious sprouting. These results indicate that endogenous ABA is essential for the induction and maintenance of potato microtuber dormancy. PMID:12232251

Suttle, J. C.; Hultstrand, J. F.

1994-07-01

213

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

PubMed

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 and seed longevity described as two traits. Seed dormancy is defined as a temporary failure of a viable seed to germinate in conditions that favor germination, whereas seed longevity is defined as seed viability after dry storage (storability). In plants, the association of seed longevity with seed dormancy has not been studied in detail. This is surprising given the ecological, agronomical, and economic importance of seed longevity. We studied seed longevity to reveal its genetic regulators and its association with seed dormancy in Arabidopsis (Arabidopsis thaliana). Integrated quantitative trait locus analyses for seed longevity, in six recombinant inbred line populations, revealed five loci: Germination Ability After Storage1 (GAAS1) to GAAS5. GAAS loci colocated with seed dormancy loci, Delay Of Germination (DOG), earlier identified in the same six recombinant inbred line populations. Both GAAS loci and their colocation with DOG loci were validated by near isogenic lines. A negative correlation was observed, deep seed dormancy correlating with low seed longevity and vice versa. Detailed analysis on the collocating GAAS5 and DOG1 quantitative trait loci revealed that the DOG1-Cape Verde Islands allele both reduces seed longevity and increases seed dormancy. To our knowledge, this study is the first to report a negative correlation between seed longevity and seed dormancy. PMID:23085841

Nguyen, Thu-Phuong; Keizer, Paul; van Eeuwijk, Fred; Smeekens, Sjef; Bentsink, Leónie

2012-12-01

214

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

PubMed Central

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

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

2007-01-01

215

Effect of root length on epicotyl dormancy release in seeds of Paeonia ludlowii, Tibetan peony  

PubMed Central

Background and Aims Epicotyl dormancy break in seeds that have deep simple epicotyl morphophysiological dormancy (MPD) requires radicle emergence and even a certain root length in some species. However, the mechanisms by which root length affects epicotyl dormancy break are not clear at present. This study aims to explore the relationship between root length and epicotyl dormancy release in radicle-emerged seeds of Tibetan peony, Paeonia ludlowii, with discussion of the possible mechanisms. Methods Radicle-emerged seeds (radicle length 1·5, 3·0, 4·5 and 6·0 cm) were incubated at 5, 10 and 15 °C. During the stratification, some seeds were transferred to 15 °C and monitored for epicotyl–plumule growth. Hormone content was determined by ELISA, and the role of hormones in epicotyl dormancy release was tested by exogenous hormone and embryo culture. Key Results Cold stratification did not break the epicotyl dormancy until the root length was ?6 cm. The indole-3-actic acid (IAA) and GA3 contents of seeds having 6 cm roots were significantly higher than those of seeds with other root lengths, but the abscisic acid (ABA) content was lowest among radicle-emerged seeds. GA3 (400 mg L?1) could break epicotyl dormancy of all radicle-emerged seeds, while IAA (200 mg L?1) had little or no effect. When grown on MS medium, radicles of naked embryos grew and cotyledons turned green, but epicotyls did not elongate. Naked embryos developed into seedlings on a mixed medium of MS + 100 mg L?1 GA3. Conclusions A root length of ?6·0 cm is necessary for epicotyl dormancy release by cold stratification. The underlying reason for root length affecting epicotyl dormancy release is a difference in the GA3/ABA ratio in the epicotyl within radicle-emerged seeds, which is mainly as a result of a difference in ABA accumulation before cold stratification. PMID:24284815

Hao, Hai-ping; He, Zhi; Li, Hui; Shi, Lei; Tang, Yu-Dan

2014-01-01

216

Opposite Effects of Daylength and Temperature on Flowering and Summer Dormancy of Poa bulbosa  

PubMed Central

• Background and Aims The timing of flowering and summer dormancy induction plays a central role in the adaptation of Mediterranean geophytes to changes in the length of the growth season along rainfall gradients. Our aim was to analyse the role of the variation in the responses of flowering and summer dormancy to vernalization, daylength and growth temperature for the adaptation of Poa bulbosa, a perennial geophytic grass, to increasing aridity. • Methods Flowering and dormancy were studied under controlled daylengths [9?h short day (SD) vs. 16?h long day (LD)] and temperatures (16/10, 22/16 and 28/22?°C day/night) in four ecotypes originating in arid, semi-arid and mesic habitats (110, 276 and 810?mm rain year?1, respectively) and differing in flowering capacity under natural conditions: arid–flowering, semi-arid–flowering, semi-arid–non-flowering and mesic–non-flowering. • Key Results Flowering and dormancy were affected in opposite ways by daylength and growth temperature. Flowering occurred almost exclusively under SD. In contrast, plants became dormant much earlier under LD than under SD. In both daylengths, high temperature and pre-chilling (6 weeks at 5?°C) enhanced dormancy imposition, but inhibited or postponed flowering, respectively. Induction of flowering and dormancy in the different ecotypes showed differential responsiveness to daylength and temperature. Arid and semi-arid ecotypes had a higher proportion of flowering plants and flowering tillers as well as more panicles per plant than mesic ecotypes. ‘Flowering’ ecotypes entered dormancy earlier than ‘non-flowering’ ecotypes, while the more arid the site of ecotype origin, the earlier the ecotype entered dormancy. • Conclusions Variation in the flowering capacity of ecotypes differing in drought tolerance was interpreted as the result of balanced opposite effects of daylength and temperature on the flowering and dormancy processes. PMID:16467351

OFIR, MICHA; KIGEL, JAIME

2006-01-01

217

1. GENERAL VIEW OF ENTRANCE INTO ALUMINUM CITY TERRACE ALONG ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. GENERAL VIEW OF ENTRANCE INTO ALUMINUM CITY TERRACE ALONG EAST HILL DRIVE. BUILDING 1 ON RIGHT, BUILDING 2 ON LEFT, FACING EAST. - Aluminum City Terrace, East Hill Drive, New Kensington, Westmoreland County, PA

218

Physical, Chemical, and Biological Oceanography of the Entrance to the  

E-print Network

part of the Scripps Tuna Oceanography Research Program, Institute of Marine Resources, University573 Physical, Chemical, and Biological Oceanography of the Entrance to the Gulf of California and Wildlife Service BUREAU OF COMMERCIAL FISHERIES Physical, Chemical, and Biological Oceanography

219

2. Water treatment plant entrance, view to W Fort ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Water treatment plant entrance, view to W - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

220

Detail of stairway and main entrance on west front of ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail of stairway and main entrance on west front of center block, showing steps and frame canopy. View to southeast. - Southern Ute Boarding School, Boy's Dormitory, Ouray & Capote Drives, Ignacio, La Plata County, CO

221

5. DETAIL OF ENTRANCE OF 14 LOGAN CIRCLE WITH SIDE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. DETAIL OF ENTRANCE OF 14 LOGAN CIRCLE WITH SIDE BAY OF 1500 THIRTEENTH STREET NW ON RIGHT. - Logan Circle, Vermont Avenue, Rhode Island Avenue, & Thirteenth Street, Washington, District of Columbia, DC

222

70. Smart view recreation area entrance road. View of the ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

70. Smart view recreation area entrance road. View of the snake or worm fences used to reinforce the roadway alignment. Looking north-northwest. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

223

4. SULLIVAN TAILING PILE. CAMERA POINTED WEST. MINE ENTRANCE IS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. SULLIVAN TAILING PILE. CAMERA POINTED WEST. MINE ENTRANCE IS APPROXIMATELY 30 YARDS BEHIND CAMERA POSITION. - Florida Mountain Mining Sites, Sullivan Mine, East side of Florida Mountain, Silver City, Owyhee County, ID

224

5. VIEW SOUTH FROM TERRACE LEVEL SHOWING ENTRANCE TO NURSES ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. VIEW SOUTH FROM TERRACE LEVEL SHOWING ENTRANCE TO NURSES HOME NO. 1 (RIGHT) IN LINK TO NURSES HOME NO. 3 (LEFT) - Jersey City Hospital, Nurses Homes, 112-114 Clifton Place, Jersey City, Hudson County, NJ

225

72. SECOND FLOOR, HEATER ROOM ENTRANCE (UPPER RIGHT) AND STEEL, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

72. SECOND FLOOR, HEATER ROOM ENTRANCE (UPPER RIGHT) AND STEEL, CONCRETE, BRICK, AND SPRING AIR CONDITIONER BASE, BAY 31-32/4 SOUTH, TO WEST - Ford Motor Company Edgewater Assembly Plant, Assembly Building, 309 River Road, Edgewater, Bergen County, NJ

226

LOWER RAIL SPUR INTO BESSEMER BUILDING. EAST ENTRANCE, LOOKING WEST. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

LOWER RAIL SPUR INTO BESSEMER BUILDING. EAST ENTRANCE, LOOKING WEST. - Jones & Laughlin Steel Corporation, Pittsburgh Works, Morgan Billet Mill Engine, 550 feet north of East Carson Street, opposite South Twenty-seventh Street, Pittsburgh, Allegheny County, PA

227

38. STAIRS FROM ENTRANCE AT SIXTEENTH STREET TO UPPER MALL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

38. STAIRS FROM ENTRANCE AT SIXTEENTH STREET TO UPPER MALL PARK, LOOKING SOUTH, summer 1985 - Meridian Hill Park, Bounded by Fifteenth, Sixteenth, Euclid & W Streets, Northwest, Washington, District of Columbia, DC

228

37. STAIRS TO ENTRANCE AT SIXTEENTH STREET FROM UPPER MALL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

37. STAIRS TO ENTRANCE AT SIXTEENTH STREET FROM UPPER MALL PARK, LOOKING NORTH, August 1976 - Meridian Hill Park, Bounded by Fifteenth, Sixteenth, Euclid & W Streets, Northwest, Washington, District of Columbia, DC

229

Wil Wheaton and the Grand Entrance - Duration: 4:07.  

NASA Video Gallery

As NASA prepares for Curiosity rover landing on Mars, Wil Wheaton shares this thrilling story of NASA's hardest planetary science mission to date. The video titled, "Grand Entrance," guides viewers...

230

1. EXTERIOR VIEW, LOOKING EAST, WITH ENTRANCES AND SIDE ELEVATIONS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. EXTERIOR VIEW, LOOKING EAST, WITH ENTRANCES AND SIDE ELEVATIONS ALONG THE OLD BANKHEAD HIGHWAY (NOW 20TH STREET) AND ELLIOTT BOULEVARD - G. W. Posey Store, Twentieth Street & Elliot Boulevard, Jasper, Walker County, AL

231

View of south entrance to #157 through south breezeway arches ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of south entrance to #157 through south breezeway arches - National Home for Disabled Volunteer Soldiers, Pacific Branch, Mental Health Buildings, 11301 Wilshire Boulevard, West Los Angeles, Los Angeles County, CA

232

North & south wall elevation of the east entrance loggia; ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

North & south wall elevation of the east entrance loggia; detail of pilaster base and capital - National Zoological Park, Elephant House, 3001 Connecticut Avenue NW, Washington, District of Columbia, DC

233

5. Historic American Buildings Survey PHOTOCOPY OF ORIGINAL ENTRANCE, PORCH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. Historic American Buildings Survey PHOTOCOPY OF ORIGINAL ENTRANCE, PORCH AND FENESTRATION Gilman Collection of Cambridge Photographs Now at Cambridge Historical Commission - Thomas Wentworth Higginson House, 29 Buckingham Street, Cambridge, Middlesex County, MA

234

Rear (north side), showing vehicle entrances and connecting twostory sections ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Rear (north side), showing vehicle entrances and connecting two-story sections from west roof deck - Fitzsimons General Hospital, Main Hospital Building, Charlie Kelly Boulevard, North side, at intersection of Sharon A. Lane Drive, Aurora, Adams County, CO

235

42. VIEW OF WALL AT EAST ENTRANCE TO WALKWAY. 'FRANK ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

42. VIEW OF WALL AT EAST ENTRANCE TO WALKWAY. 'FRANK AUZA, FLAGSTAFF SHEEP CO.' SCRATCHED INTO FRESH MORTAR CAP ON STONE WALL. February 1987 - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ

236

31. VIEW OF CONCRETE SLAB AT WEST ENTRANCE OF WALKWAY. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. VIEW OF CONCRETE SLAB AT WEST ENTRANCE OF WALKWAY. '1944 JOE LANDETA' SCRATCHED INTO FRESH CONCRETE. March 1987 - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ

237

1. Opposition sign posted on private property at the entrance ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Opposition sign posted on private property at the entrance to the road looking NW. - Great Smoky Mountains National Park Roads & Bridges, Northshore Road, 1 mile spur at Fontana Dam & Bryson City to Noland Creek, Gatlinburg, Sevier County, TN

238

APPROACH, ENTRANCE AND VENTILATION TOWERS OF THE LINCOLN TUNNEL, NEW ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

APPROACH, ENTRANCE AND VENTILATION TOWERS OF THE LINCOLN TUNNEL, NEW JERSEY LOOKING SOUTHWEST - Lincoln Tunnel, Under Hudson River from New Jersey to West Thirty-ninth Street, New York City, New York, New York County, NY

239

South side (red cross office entrance). Fitzsimons General Hospital, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

South side (red cross office entrance). - Fitzsimons General Hospital, Red Cross Building, South Eighth Street Bounded by West McAfee Avenue on South & West Harlow Avenue on North, Aurora, Adams County, CO

240

1. VIEW OF THE ENTRANCE TO THE HATCH ADIT (FEATURE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. VIEW OF THE ENTRANCE TO THE HATCH ADIT (FEATURE B-28), FACING WEST. (OCTOBER, 1995) - Nevada Lucky Tiger Mill & Mine, Hatch Adit, East slope of Buckskin Mountain, Paradise Valley, Humboldt County, NV

241

3. FIRST FLOOR, FRONT ROOM WITH ENTRANCE DOORS ON THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. FIRST FLOOR, FRONT ROOM WITH ENTRANCE DOORS ON THE EAST WALL - Penn School Historic District, Butler Building, SC Route 37, 1 mile South of Frogmore, St. Helena Island, Frogmore, Beaufort County, SC

242

55. VIEW OF WEST ENTRANCE BRIDGE CROSSING THE ARIZONA CANAL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

55. VIEW OF WEST ENTRANCE BRIDGE CROSSING THE ARIZONA CANAL AT THE ARIZONA BILTMORE, LOOKING EAST Photographer: Kevin Kriesel-Coons, May 1990 - Arizona Canal, North of Salt River, Phoenix, Maricopa County, AZ

243

5. Keeper's house, detail of entrance porch, southeast corner, looking ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. Keeper's house, detail of entrance porch, southeast corner, looking northwest - Ram Island Light Station, Ram Island, south of Ocean Point & just north of Fisherman Island, marking south side of Fisherman Island Passage, Ocean Point, Lincoln County, ME

244

FEATURE 4, ARMCO HUT, ENTRANCE FACADE, VIEW FACING EASTSOUTHEAST (with ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FEATURE 4, ARMCO HUT, ENTRANCE FACADE, VIEW FACING EAST-SOUTHEAST (with scale stick). - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-ARMCO Hut, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

245

FEATURE D, TYPE 1 PILLBOX, NORTH SIDE SHOWING ENTRANCE MOSTLY ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FEATURE D, TYPE 1 PILLBOX, NORTH SIDE SHOWING ENTRANCE MOSTLY BURIED IN SAND, VIEW FACING SOUTHEAST. - Naval Air Station Barbers Point, Shore Pillbox Complex-Type 1 Pillbox, Along shoreline, seaward of Coral Sea Road, Ewa, Honolulu County, HI

246

FEATURE 4, ARMCO HUT, ENTRANCE FACADE, VIEW FACING EASTSOUTHEAST. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

FEATURE 4, ARMCO HUT, ENTRANCE FACADE, VIEW FACING EAST-SOUTHEAST. - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-ARMCO Hut, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

247

2. DETAIL, EAST ENTRANCE, SHOWING OUTER BLAST DOOR AND INNER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. DETAIL, EAST ENTRANCE, SHOWING OUTER BLAST DOOR AND INNER DOORS. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Instrumentation & Control Building, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

248

14. Inner double blast door entrance to perimeter acquisition radar ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. Inner double blast door entrance to perimeter acquisition radar building security area - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

249

20. Upper level equipment room, further left from entrance. Lyon ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. Upper level equipment room, further left from entrance. Lyon - Whiteman Air Force Base, Minuteman Missile Launch Facility Trainer T-12, Northeast of Oscar-01 Missile Alert Facility, Knob Noster, Johnson County, MO

250

19. Upper level equipment room, left from entrance. Lyon ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. Upper level equipment room, left from entrance. Lyon - Whiteman Air Force Base, Minuteman Missile Launch Facility Trainer T-12, Northeast of Oscar-01 Missile Alert Facility, Knob Noster, Johnson County, MO

251

5. BUILDING 0503, INTERIOR WOODEN ARCHES. Looking south from entrance. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. BUILDING 0503, INTERIOR WOODEN ARCHES. Looking south from entrance. - Edwards Air Force Base, South Base Sled Track, Earth Covered Bunker Types, North of Sled Track, Lancaster, Los Angeles County, CA

252

1. Roaring Fork Motor Nature Trail, entrance sign. Great ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Roaring Fork Motor Nature Trail, entrance sign. - Great Smoky Mountains National Park Roads & Bridges, Roaring Fork Motor Nature Trail, Between Cherokee Orchard Road & U.S. Route 321, Gatlinburg, Sevier County, TN

253

8. LOOKING SOUTHWEST, SHOWING DETAIL OF PORCHED ENTRANCE TO STORAGE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. LOOKING SOUTHWEST, SHOWING DETAIL OF PORCHED ENTRANCE TO STORAGE AREA, AND NORTHEAST CORNER OF DINING ROOM IN BACKGROUND - Camp Cleawox Organizational Tract, Lodge Building, Oregon Dunes National Recreation Area, Siuslaw National Forest, Florence, Lane County, OR

254

Interior view, stairwell and entrance to the great hall (note ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior view, stairwell and entrance to the great hall (note Boardman Roberts's painting, Great Codifers of Law) - United States Department of Justice, Constitution Avenue between Ninth & Tenth Streets, Northwest, Washington, District of Columbia, DC

255

TENANT HOUSE INTERIOR, DOOR DETAIL, FRONT ENTRANCE INTO LIVING ROOM, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

TENANT HOUSE INTERIOR, DOOR DETAIL, FRONT ENTRANCE INTO LIVING ROOM, LOOKING NORTH - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

256

1. Old road alignment, now entrance to government parking area, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Old road alignment, now entrance to government parking area, facing 24 degrees north northeast - Oak Creek Administrative Center, One half mile east of Zion-Mount Carmel Highway at Oak Creek, Springdale, Washington County, UT

257

15. ROOMS 48 AND 49, LOOKING SOUTH FROM ENTRANCE TO ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. ROOMS 48 AND 49, LOOKING SOUTH FROM ENTRANCE TO ROOM 47. THE OAK CABINETS ARE USED TO STORE ROCK CORE SAMPLES. - U.S. Geological Survey, Rock Magnetics Laboratory, 345 Middlefield Road, Menlo Park, San Mateo County, CA

258

EXTERIOR VIEW, LOOKING EAST, FRONT FACADE AND ENTRANCE TO COMPANY ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

EXTERIOR VIEW, LOOKING EAST, FRONT FACADE AND ENTRANCE TO COMPANY SCHOOL FOR CHILDREN OF BLACK TCI-US STEEL RED ORE MINE WORKERS - Company School for Blacks, 413 Morgan Road, Bessemer, Jefferson County, AL

259

2. MAGAZINE P, WITH ENTRANCE DOOR IN FOREGROUND, LOOKING NORTHEAST. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. MAGAZINE P, WITH ENTRANCE DOOR IN FOREGROUND, LOOKING NORTHEAST. - NIKE Missile Base C-84, Underground Storage Magazines & Launcher-Loader Assemblies, Easternmost portion of launch area, Barrington, Cook County, IL

260

9. MAGAZINE P INTERIOR, LOOKING TO DOORWAY ENTRANCE. NIKE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. MAGAZINE P INTERIOR, LOOKING TO DOORWAY ENTRANCE. - NIKE Missile Base C-84, Underground Storage Magazines & Launcher-Loader Assemblies, Easternmost portion of launch area, Barrington, Cook County, IL

261

10. SOUTHEAST CORNER OF OLD THEODOLITE BUILDING; ENTRANCE ON EAST ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. SOUTHEAST CORNER OF OLD THEODOLITE BUILDING; ENTRANCE ON EAST SIDE. SOUTHEAST CORNER OF MST IN BACKGROUND. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

262

24. LAUNCH CONTROL CAPSULE. ENTRANCE TO ACOUSTICAL ENCLOSURE. SHOCK ISOLATOR ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. LAUNCH CONTROL CAPSULE. ENTRANCE TO ACOUSTICAL ENCLOSURE. SHOCK ISOLATOR AT FAR LEFT. VIEW TO NORTH. - Minuteman III ICBM Launch Control Facility November-1, 1.5 miles North of New Raymer & State Highway 14, New Raymer, Weld County, CO

263

72. Detail of keystone emblem over the main entrance to ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

72. Detail of keystone emblem over the main entrance to the Carpenter's Union Hall. The inscription translates 'Labor conquers all.' - Butte Historic District, Bounded by Copper, Arizona, Mercury & Continental Streets, Butte, Silver Bow County, MT

264

17. DETAILED VIEW OF THE ENTRANCE OF THE COTTON WOOD ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. DETAILED VIEW OF THE ENTRANCE OF THE COTTON WOOD PRESSURE PIPE Photographer: Walter J. Lubken, March 9, 1906 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ

265

28. MAIN ENTRANCE IN EAST FACADELEVEL, FRONTAL NORMAL ANGLE Copy ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

28. MAIN ENTRANCE IN EAST FACADE--LEVEL, FRONTAL NORMAL ANGLE Copy photograph of photogrammetric plate LC-HABS-FS13-B-1974-827R. - St. Mary's Seminary, 600 North Paca Street, Baltimore, Independent City, MD

266

1. GENERAL VIEW OF SOUTH SIDE ELEVATION FROM ENTRANCE GATE, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. GENERAL VIEW OF SOUTH SIDE ELEVATION FROM ENTRANCE GATE, WITH NEW CHURCH ON RIGHT - Valley Grove Churches, Old Church, County Road 29, 1/4 mile from Minnesota Highway 246, Nerstrand, Rice County, MN

267

A study of driver behavior on freeway entrance ramps  

E-print Network

A STUDY OF DRIVER BEHAVIOR ON FREEWAY ENTRANCE RAMPS A Thesis By FRED HUNTLEY EDWARDS Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE August 1961 Major Subject: Civil Engineering A STUDY OF DRIVER BEHAVIOR ON FREEWAY ENTRANCE RAMPS A Thesis By FRED HUNTLEY EDWARDS Approved as to style and content by: Chairman of Committee Head of Department August 1961 TABLE...

Edwards, Fred Huntley

1961-01-01

268

Imaging Spectrometer Designs Utilizing Immersed Gratings With Accessible Entrance Slit  

SciTech Connect

A compact imaging spectrometer comprises an entrance slit, a catadioptric lens with a mirrored surface, a grating, and a detector array. The entrance slit directs light to the mirrored surface of the catadioptric lens; the mirrored surface reflects the light back through the lens to the grating. The grating receives the light from the catadioptric lens and diffracts the light to the lens away from the mirrored surface. The lens transmits the light and focuses it onto the detector array.

Chrisp, Michael P. (Danville, CA); Lerner, Scott A. (Corvallis, OR)

2006-03-21

269

Bud and Yvonne, still imageSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

Bud and Yvonne are delighted by Bud's recovery thanks to Gleevec. Diagnosed with chronic myeloid leukemia (CML), Bud noticed an article in the newspaper on Brian Druker's research. Bud and his wife Yvonne contacted Druker in 1996, and Bud was the first patient to receive the drug STI-571 (Gleevec) in clinical trials.

2008-10-06

270

Nitroguanidines induce bud break and change sterol content in apple  

Microsoft Academic Search

Bud break in apple (Malus domestica Borkh cv. Golden Delicious) was induced by 1-(3,5-dichlorophenyl)-3-nitroguanidine or 1-(?-ethylbenzyl)-3-nitroguanidine.\\u000a The optimum dose was 1000 ?M. An increase in bud fresh weight, dry weight, and length was more prominent in buds treated with\\u000a 1-(?-ethylbenzyl)-3-nitroguanidine than in those treated with 1-(3,5-dichlorophenyl)-3-nitroguanidine. The sterol compositional\\u000a changes during bud break induced by 1-(3,5-dichlorophenyl)-3-nitroguanidine were similar to those

S. Y. Wang; M. Faust

1989-01-01

271

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

SciTech Connect

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.

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

1992-03-01

272

Essential Oil of Betula pendula Roth. Buds  

PubMed Central

The essential oil of Betula pendula Roth. buds was obtained using both hydrodistillation and microdistillation techniques and their chemical compositions were analyzed using both gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS). Overall, more than 50 compounds were identified representing 80% and 92% for hydrodistillation and microdistillation, respectively. The main components (by hydrodistillation and microdistillation, respectively) found were ?-copaene (12% and 10%), germacrene D (11% and 18%) and ?-cadinene (11% and 15%) in the analyzed essential oils. The microdistillation technique proved to be a useful tool and compliant alternative when compared to hydrodistillation. PMID:15841263

2004-01-01

273

The involvement of ethylene in the release of primary dormancy in Amaranthus retroflexus seeds  

Microsoft Academic Search

Primary dormancy in A. retroflexus seeds wascompletely broken by dry storage or ethylene treatment and partially removedwith GA3. Norbornadiene counteracted the dormancy breaking action ofethylene and GA3. The GA3 effect was lowered bycobaltous ions. ABA increased the ethylene requirement in primary dormant seeds.Dormant seeds had a similar or different ability to produce ethylene and ACCoxidase in vivo activity than did

J. K?pczy?ski; E. K?pczy?ska; M. Bihun

2003-01-01

274

Comparative transcriptome profiling of developing caryopses from two rice cultivars with differential dormancy.  

PubMed

Pre-harvest sprouting (PHS) in rice causes poor grain quality and results in significant reductions in yield, leading to significant economic losses. In contrast, deep dormancy can lead to equally unwanted non-uniform germination. Therefore, a suitable level of dormancy is a critically important agronomic trait. In this study, an analysis of PHS in developing seeds of two Korean rice cultivars (vivipary), Gopum and Samgwang, revealed differences in dormancy in caryopses at 25 d after heading (DAH). To assess the transcriptomic characteristics associated with vivipary, we compared RNA profiles at early (3-6 DAH), middle (25 DAH), and late (40 DAH) developmental stages. Transcriptomic differentiation was most pronounced in caryopses at 25 DAH, the developmental stage at which differential dormancy was also the most prominent. A k-means clustering analysis of the two cultivars revealed groups of genes with similar or dissimilar expression profiles. Many of the genes that showed distinct differential expression profiles were those involved in seed maturation. Intriguingly, differential gene expression levels between the two cultivars were positively correlated with fold-changes in their expression during the early half of caryopsis development. This implies that the establishment of seed dormancy is strongly correlated with the altered transcriptomic patterns related to the progression of maturation. Our global RNA profiling suggests that caryopsis development in Gopum proceeds at a greater speed than in the Samgwang cultivar. Thus, a high degree of maturity and early dormancy release may be present in 25 DAH caryopses of Gopum, although we cannot exclude the possibility of genetic defects modifying dormancy. The comparative transcriptomic analysis of the two cultivars did not reveal noticeable differences in RNA profiles with respect to differences in abscisic acid (ABA) content or ABA sensitivity. Therefore, it is unlikely that ABA is directly involved in the differences in dormancy observed between the two cultivars. PMID:23579068

Huh, Sun Mi; Hwang, Yong-sic; Shin, Young Seop; Nam, Myung Hee; Kim, Dool Yi; Yoon, In Sun

2013-08-15

275

Dormancy and germination of six Rhinanthus species in relation to climate  

Microsoft Academic Search

The genusRhinanthus (Orobanchaceae) consists of annual hemiparasites that occur in a wide range of climates. Patterns of dormancy and germination were studied\\u000a for six species sampled in areas ranging from the Pyrenees to Northern Scandinavia, and from sea level up to about 2500 m\\u000a altitude in the Alpine region. Dormancy was broken by a 2 to 6 months period of

Siny J. Ter Borg

2005-01-01

276

Dormancy patterns, germination ecology, and seed-bank types of twenty temperate fen grassland species  

Microsoft Academic Search

The germination ecology, including primary and secondary dormancy, mortality of seeds, and seed-bank type, of 20 fen grassland\\u000a species from Northern Germany was investigated using a combination of burial and germination experiments. To analyze primary\\u000a dormancy and effects of after-ripening (dry storage for 28 days) on freshly matured seeds, germination was measured at two\\u000a fluctuating temperature regimes (15\\/25°C and 5\\/15°C)

Kai Jensen

2004-01-01

277

Obscured phylogeny and possible recombinational dormancy in Escherichia coli  

PubMed Central

Background Escherichia coli is one of the best studied organisms in all of biology, but its phylogenetic structure has been difficult to resolve with current data and analytical techniques. We analyzed single nucleotide polymorphisms in chromosomes of representative strains to reconstruct the topology of its emergence. Results The phylogeny of E. coli varies according to the segment of chromosome analyzed. Recombination between extant E. coli groups is largely limited to only three intergroup pairings. Conclusions Segment-dependent phylogenies most likely are legacies of a complex recombination history. However, E. coli are now in an epoch in which they no longer broadly share DNA. Using the definition of species as organisms that freely exchange genetic material, this recombinational dormancy could reflect either the end of E. coli as a species, or herald the coalescence of E. coli groups into new species. PMID:21708031

2011-01-01

278

RNA-Seq transcriptome analysis of Spirodela dormancy without reproduction  

PubMed Central

Background Higher plants exhibit a remarkable phenotypic plasticity to adapt to adverse environmental changes. The Greater Duckweed Spirodela, as an aquatic plant, presents exceptional tolerance to cold winters through its dormant structure of turions in place of seeds. Abundant starch in turions permits them to sink and escape the freezing surface of waters. Due to their clonal propagation, they are the fastest growing biomass on earth, providing yet an untapped source for industrial applications. Results We used next generation sequencing technology to examine the transcriptome of turion development triggered by exogenous ABA. A total of 208 genes showed more than a 4-fold increase compared with 154 down-regulated genes in developing turions. The analysis of up-regulated differential expressed genes in response to dormancy exposed an enriched interplay among various pathways: signal transduction, seed dehydration, carbohydrate and secondary metabolism, and senescence. On the other side, the genes responsible for rapid growth and biomass accumulation through DNA assembly, protein synthesis and carbon fixation are repressed. Noticeably, three members of late embryogenesis abundant protein family are exclusively expressed during turion formation. High expression level of key genes in starch synthesis are APS1, APL3 and GBSSI, which could artificially be reduced for re-directing carbon flow from photosynthesis to create a higher energy biomass. Conclusions The identification and functional annotation of differentially expressed genes open a major step towards understanding the molecular network underlying vegetative frond dormancy. Moreover, genes have been identified that could be engineered in duckweeds for practical applications easing agricultural production of food crops. PMID:24456086

2014-01-01

279

Environmental control of ovarian dormancy in natural populations of Drosophila melanogaster.  

PubMed

Drosophila melanogaster from Australia, Europe and North America enter an adult ovarian dormancy in response to short days and low temperatures. The independent effects of temperature and day length in the determination of dormancy have been examined only in one long-established laboratory line (Canton-S). In all other studies of natural or laboratory populations, dormancy has been assessed at either a single short day or a single moderately low temperature. Herein, we determine the relative roles of temperature, photoperiod, and their interaction in the control of ovarian dormancy in D. melanogaster from two natural populations representing latitudinal extremes in eastern North America (Florida at 27 degrees N and Maine at 44 degrees N). In both natural populations, temperature is the main determinant of dormancy, alone explaining 67% of the total variation among replicate isofemale lines, whereas photoperiod has no significant effect. We conclude that ovarian dormancy in D. melanogaster is a temperature-initiated syndrome of winter-tolerant traits that represents an adaptive phenotypic plasticity in temperate seasonal environments. PMID:19669646

Emerson, Kevin J; Uyemura, Alison M; McDaniel, Keely L; Schmidt, Paul S; Bradshaw, William E; Holzapfel, Christina M

2009-09-01

280

ABA inhibits germination but not dormancy release in mature imbibed seeds of Lolium rigidum Gaud.  

PubMed Central

Dormancy release in imbibed annual ryegrass (Lolium rigidum Gaud.) seeds is promoted in the dark but inhibited in the light. The role of abscisic acid (ABA) in inhibition of dormancy release was found to be negligible, compared with its subsequent effect on germination of dormant and non-dormant seeds. Inhibitors of ABA metabolism had the expected effects on seed germination but did not influence ABA concentration, suggesting that they act upon other (unknown) factors regulating dormancy. Although gibberellin (GA) synthesis was required for germination, the influence of exogenous GA on both germination and dormancy release was minor or non-existent. Embryo ABA concentration was the same following treatments to promote (dark stratification) and inhibit (light stratification) dormancy release; exogenous ABA had no effect on this process. However, the sensitivity of dark-stratified seeds to ABA supplied during germination was lower than that of light-stratified seeds. Therefore, although ABA definitely plays a role in the germination of annual ryegrass seeds, it is not the major factor mediating inhibition of dormancy release in imbibed seeds. PMID:19487389

Goggin, Danica E.; Steadman, Kathryn J.; Emery, R. J. Neil; Farrow, Scott C.; Benech-Arnold, Roberto L.; Powles, Stephen B.

2009-01-01

281

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

PubMed Central

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 quantitative trait loci (QTL) mapping approach to identify loci affecting the after-ripening requirement measured as the number of days of seed dry storage required to reach 50% germination. Thus, seven QTL were identified and named delay of germination (DOG) 1-7. To confirm and characterize these loci, we developed 12 near-isogenic lines carrying single and double Cvi introgression fragments in a Ler genetic background. The analysis of these lines for germination in water confirmed four QTL (DOG1, DOG2, DOG3, and DOG6) as showing large additive effects in Ler background. In addition, it was found that DOG1 and DOG3 genetically interact, the strong dormancy determined by DOG1-Cvi alleles depending on DOG3-Ler alleles. These genotypes were further characterized for seed dormancy/germination behavior in five other test conditions, including seed coat removal, gibberellins, and an abscisic acid biosynthesis inhibitor. The role of the Ler/Cvi allelic variation in affecting dormancy is discussed in the context of current knowledge of Arabidopsis germination. PMID:12807791

Alonso-Blanco, Carlos; Bentsink, Leónie; Hanhart, Corrie J; Blankestijn-de Vries, Hetty; Koornneef, Maarten

2003-01-01

282

The qSD12 Locus Controls Offspring Tissue-Imposed Seed Dormancy in Rice  

PubMed Central

Seed component structures were grouped into maternal and offspring (embryo and endosperm) tissues to characterize a dormancy quantitative trait locus (QTL) for tissue-specific function using a marker-assisted genetic approach. The approach was devised to test if genotypic/allelic frequencies of a marker tightly linked to the QTL deviate from Mendelian expectations in germinated and nongerminated subpopulations derived from a segregation population of partially after-ripened seeds and was applied to the dormancy QTL qSD12 and qSD7-1 in a nearly isogenic background of rice. Experimental results unambiguously demonstrated that qSD12 functions in the offspring tissue(s) and suggested that qSD7-1 may control dormancy through the maternal tissues. These experiments also provide the first solid evidence that an offspring tissue-imposed dormancy gene contributes to the segregation distortion in a mapping population developed from partially after-ripened seeds and, in part, to the germination heterogeneity of seeds from hybrid plants. Offspring and maternal tissue-imposed dormancy genes express in very early and late stages of the life cycle, respectively, and interact to provide the species with complementary adaptation strategies. The qSD12 locus was narrowed to the region of ?600 kbp on a high-resolution map to facilitate cloning and marker-assisted selection of the major dormancy gene. PMID:18711220

Gu, Xing-You; Turnipseed, E. Brent; Foley, Michael E.

2008-01-01

283

Electrochemical regulation of budding yeast polarity.  

PubMed

Cells are naturally surrounded by organized electrical signals in the form of local ion fluxes, membrane potential, and electric fields (EFs) at their surface. Although the contribution of electrochemical elements to cell polarity and migration is beginning to be appreciated, underlying mechanisms are not known. Here we show that an exogenous EF can orient cell polarization in budding yeast (Saccharomyces cerevisiae) cells, directing the growth of mating projections towards sites of hyperpolarized membrane potential, while directing bud emergence in the opposite direction, towards sites of depolarized potential. Using an optogenetic approach, we demonstrate that a local change in membrane potential triggered by light is sufficient to direct cell polarization. Screens for mutants with altered EF responses identify genes involved in transducing electrochemical signals to the polarity machinery. Membrane potential, which is regulated by the potassium transporter Trk1p, is required for polarity orientation during mating and EF response. Membrane potential may regulate membrane charges through negatively charged phosphatidylserines (PSs), which act to position the Cdc42p-based polarity machinery. These studies thus define an electrochemical pathway that directs the orientation of cell polarization. PMID:25548923

Haupt, Armin; Campetelli, Alexis; Bonazzi, Daria; Piel, Matthieu; Chang, Fred; Minc, Nicolas

2014-12-01

284

Electrochemical Regulation of Budding Yeast Polarity  

PubMed Central

Cells are naturally surrounded by organized electrical signals in the form of local ion fluxes, membrane potential, and electric fields (EFs) at their surface. Although the contribution of electrochemical elements to cell polarity and migration is beginning to be appreciated, underlying mechanisms are not known. Here we show that an exogenous EF can orient cell polarization in budding yeast (Saccharomyces cerevisiae) cells, directing the growth of mating projections towards sites of hyperpolarized membrane potential, while directing bud emergence in the opposite direction, towards sites of depolarized potential. Using an optogenetic approach, we demonstrate that a local change in membrane potential triggered by light is sufficient to direct cell polarization. Screens for mutants with altered EF responses identify genes involved in transducing electrochemical signals to the polarity machinery. Membrane potential, which is regulated by the potassium transporter Trk1p, is required for polarity orientation during mating and EF response. Membrane potential may regulate membrane charges through negatively charged phosphatidylserines (PSs), which act to position the Cdc42p-based polarity machinery. These studies thus define an electrochemical pathway that directs the orientation of cell polarization. PMID:25548923

Piel, Matthieu; Chang, Fred; Minc, Nicolas

2014-01-01

285

Fatty acid composition of black bear ( Ursus americanus ) milk during and after the period of winter dormancy  

Microsoft Academic Search

Black bears give birth and lactate during the 2–3-mon fast of winter dormancy. Thereafter the female emerges from the den\\u000a with her cubs and begins to feed. We investigated fatty acid patterns of milk from native Pennsylvania black bears during\\u000a the period of winter dormancy, as well as after den emergence. Throughout winter dormancy, milk fatty acid composition remained\\u000a relatively

Sara J. Iversona; Olav T. Oftedal

1992-01-01

286

Cycling of Sensitivity to Physical Dormancy-break in Seeds of Ipomoea lacunosa (Convolvulaceae) and Ecological Significance  

PubMed Central

Background and Aims Although a claim has been made that dormancy cycling occurs in seeds of Ipomoea lacunosa (Convolvulaceae) with physical dormancy, this would seem to be impossible since the water gap cannot be closed again after it opens (dormancy break). On the other hand, changes in sensitivity (sensitive ? non-sensitive) to dormancy-breaking factors have been reported in seeds of Fabaceae with physical dormancy. The primary aim of the present study was to determine if sensitivity cycling also occurs in physically dormant seeds of I. lacunosa. Methods Treatments simulating conditions in the natural habitat of I. lacunosa were used to break seed dormancy. Storage of seeds at temperatures simulating those in spring, summer, autumn and winter were tested for their effect on sensitivity change. Seeds made non-dormant were stored dry in different temperature regimes to test for dormancy cycling. In addition, seeds collected on different dates (i.e. matured under different climatic conditions) were used to test for maternal effects on sensitivity to dormancy-breaking factors. Key Results Sensitivity was induced by storing seeds under wet conditions and reversed by storing them under dry conditions at low (?5 °C) or high (?30 °C) temperatures, demonstrating that seeds of I. lacunosa can cycle between sensitive and insensitive states. Sensitive seeds required ?2 h at 35 °C on moist sand for release of dormancy. However, there is no evidence to support dormancy cycling per se. Conceptual models are proposed for sensitivity cycling and germination phenology of I. lacunosa in the field. Conclusions Seasonal germination behaviour of physically dormant I. lacunosa seeds can be explained by sensitivity cycling but not by dormancy cycling per se. Convolvulaceae is only the second of 16 families known to contain species with physical dormancy for which sensitivity cycling has been demonstrated. PMID:18032427

Jayasuriya, K. M. G. G.; Baskin, J. M.; Baskin, C. C.

2008-01-01

287

Are budburst dates, dormancy and cold acclimation in walnut trees (Juglans regia L.) under mainly genotypic or environmental control?  

PubMed

As observed for most stresses, tree frost resistance can be split into two main processes: avoidance and tolerance. Avoidance of freezing is achieved by introducing species only in the climatic context in which the probability of freezing events is very low for the sensitive stages of buds or stems; i.e., when good synchronism exists between the annual cycle and the critical climatic periods. Buds become able to grow only after chilling requirements have been satisfied (endodormancy released) during winter; they subsequently break after heat requirements have been completed (end of ecodormancy) in early spring. Actually, this period is often subject to more or less severe freezing events. Trees are also able to adjust their freezing tolerance by increasing their capacity of extracellular freezing and decreasing the possibility of intracellular freezing through the process of frost acclimation. Both freezing resistance processes (avoidance and tolerance) are environmentally driven (by photoperiod and temperature), but there are also genotypic effects among species or cultivars. Here, we evaluated the degree to which differences in dormancy release and frost acclimation were related to environmental and genetic influences by comparing trees growing in common garden conditions. This investigation was carried out for two winters in lowland and mountain locations on different walnut genotypes differing significantly for budburst dates. Chilling requirement for endodormancy release and heat requirement during ecodormancy were evaluated in all situations. In addition, frost acclimation was assessed by the electrolyte leakage method on stems from the same trees before leaf fall through budburst. No significant differences were observed in chilling requirements among genotypes. Moreover, frost acclimation dynamics were similar between genotypes or locations when expressed depending on chilling units accumulated since 15 September as a time basis instead of Julian day. The only exception was for maximal frost hardiness observed during winter with the timber-oriented being significantly more resistant than fruit-oriented genotypes. Heat requirement was significantly different among genotypes. Thus, growth was significantly faster in fruit-oriented than in wood-oriented genotypes. Furthermore, among wood-oriented genotypes, differences in growth rate were observed only at cold temperatures. Frost acclimation changes differed significantly between fruit- and wood- walnuts from January through budburst. In conclusion, from September through January, the acclimation dynamic was driven mainly by environmental factors whereas from January through budburst a significant genotype effect was identified in both frost tolerance and avoidance processes. PMID:21805380

Charrier, Guillaume; Bonhomme, Marc; Lacointe, André; Améglio, Thierry

2011-11-01

288

Buds on Actinidia arguta shoots do contain axillary meristems  

Microsoft Academic Search

First?order axillary buds from Actinidia arguta (Siebold et Zucc.) Planch, ex Miq. shoots were shown to develop second?order axillary structures in the first growing season of their development. This is contrary to what has been reported earlier. More importantly, the now revised description of A. arguta bud development does not support the hypothesis that flower evocation in kiwifruit (Actinidia deliciosa

E. F. Walton

1999-01-01

289

APC mutation and tumour budding in colorectal cancer  

Microsoft Academic Search

Aim: To determine the frequency of tumour budding and somatic APC mutation in a series of colorectal cancers stratified according to DNA microsatellite instability (MSI) status.Material\\/Methods: Ninety five colorectal cancers were genotyped for APC mutation in the mutation cluster region (exon 15) and scored for the presence of tumour budding at the invasive margin in haematoxylin and eosin stained sections.

J R Jass; M Barker; L Fraser; M D Walsh; V L J Whitehall; B Gabrielli; J Young; B A Leggett

2003-01-01

290

Encapsulation of micropropagated buds of six woody species  

Microsoft Academic Search

Regrowth after encapsulation in a sodium alginate matrix of micropropagated buds from six different in vitro proliferated woody species was evaluated. Actinidia deliciosa Liang & Ferguson (kiwifruit), Betula pendula Roth (birch), Crataegus oxyacantha L. (hawthorn), Malus spp. (apple), Rubus spp. (blackberry) and Rubus idaeus L. (raspberry) propagated in vitro were used as bud sources. Encapsulation with sodium alginate and subsequent

Emanuele Piccioni; Alvaro Standardi

1995-01-01

291

Isolation of glucanase-containing vesicles from budding yeast  

Microsoft Academic Search

In an investigation of the role of glucanases in modifying yeast cell walls at the location of new buds, vesicles derived from the endoplasmic reticulum, which are secreted locally into the cell wall of growing buds, and may be involved in the secretion of glucanases, have been isolated.

M. Cortat; P. Matile; A. Wiemken

1972-01-01

292

An elastic model of partial budding of retroviruses  

NASA Astrophysics Data System (ADS)

Retroviruses are characterized by their unique infection strategy of reverse transcription, in which the genetic information flows from RNA back to DNA. The most well known representative is the human immunodeficiency virus (HIV). Unlike budding of traditional enveloped viruses, retrovirus budding happens together with the formation of spherical virus capsids at the cell membrane. Led by this unique budding mechanism, we proposed an elastic model of retrovirus budding in this work. We found that if the lipid molecules of the membrane are supplied fast enough from the cell interior, the budding always proceeds to completion. In the opposite limit, there is an optimal size of partially budded virions. The zenith angle of these partially spherical capsids, ?, is given by ?˜(2?/??)^1/4, where ? is the bending modulus of the membrane, ? is the surface tension of the membrane, and ? characterizes the strength of capsid protein interaction. If ? is large enough such that ?˜?, the budding is complete. Our model explained many features of retrovirus partial budding observed in experiments.

Zhang, Rui; Nguyen, Toan

2008-03-01

293

Photocontrol of bud burst involves gibberellin biosynthesis in Rosa sp.  

PubMed

Light is a critical determinant of plant shape by controlling branching patterns and bud burst in many species. To gain insight into how light induces bud burst, we investigated whether its inductive effect in rose was related to gibberellin (GA) biosynthesis. In axillary buds of beheaded plants subject to light, the expression of two GA biosynthesis genes (RoGA20ox and RoGA3ox) was promptly and strongly induced, while that of a GA-catabolism genes (RoGA2ox) was reduced. By contrast, lower expression levels of these two GA biosynthesis genes were found in darkness, and correlated with a total inhibition of bud burst. This effect was dependent on both light intensity and quality. In in vitro cultured buds, the inductive effect of light on the growth of preformed leaves and SAM organogenic activity was inhibited by ancymidol and paclobutrazol, two effectors of GA biosynthesis. This effect was concentration-dependent, and negated by GA(3). However, GA(3) alone could not rescue bud burst in the dark. GA biosynthesis was also required for the expression and activity of a vacuolar invertase, and therefore for light-induced sugar metabolism within buds. These findings are evidence that GA biosynthesis contributes to the light effect on bud burst and lay the foundations of a better understanding of its exact role in plant branching. PMID:22749285

Choubane, Djillali; Rabot, Amélie; Mortreau, Eric; Legourrierec, Jose; Péron, Thomas; Foucher, Fabrice; Ahcène, Youyou; Pelleschi-Travier, Sandrine; Leduc, Nathalie; Hamama, Latifa; Sakr, Soulaiman

2012-09-01

294

Thermal entrance length in falling liquid film heat transfer  

SciTech Connect

Subcooled and evaporating falling liquid films are frequently encountered in the process industry, desalination, and nuclear reactor safety. Thermal entrance lengths in a subcooled falling liquid film were studied experimentally on a vertical cylindrical heater preceded by an adiabatic section. A wavy-laminar flow regime close to the transition to turbulent flow was achieved. Water at atmospheric pressure was used as the test fluid. Heating surface temperatures were measured at eight axial locations along the flow direction and the local heat transfer coefficients were obtained as functions of heat flux and mass flow rate. Heat transfer coefficients were observed decreasing along the heater and reaching a minimum. The influences of the Reynolds number and heat flux on the thermal entrance length at low heat fluxes were weak. Both the Reynolds number and the heat flux strongly influenced the thermal entrance length at relatively high heat fluxes.

Ulucakli, E. [Lafayette Coll., Easton, PA (United States). Dept. of Mechanical Engineering

1996-06-01

295

An Experimental Investigation of NACA Submerged-Duct Entrances  

NASA Technical Reports Server (NTRS)

The results of a preliminary investigation of submerged duct entrances are presented. It is shown that an entrance of this type possess desirable critical speed and pressure recovery characteristics when used on a fuselage or nacelle in a region of low incremental velocity and thin boundary layer. The data obtained indicate that submerged entrances are most suitable for use with internal-flow systems which diffuse the air only a small amount: for example, those used with jet motors which have axial-flow compressors. Where complete diffusion of the air is required, fuselage-nose or wing leading edge inlets may prove to be superior. The results of the investigation have been prepared in such a form as to permit their use by a designer and the application of these data to a specific design is discussed.

Frick, Charles W.; Davis, Wallace F.; Randall, Lauros M.; Mossman, Emmet A.

1945-01-01

296

Budding yeast for budding geneticists: a primer on the Saccharomyces cerevisiae model system.  

PubMed

The budding yeast Saccharomyces cerevisiae is a powerful model organism for studying fundamental aspects of eukaryotic cell biology. This Primer article presents a brief historical perspective on the emergence of this organism as a premier experimental system over the course of the past century. An overview of the central features of the S. cerevisiae genome, including the nature of its genetic elements and general organization, is also provided. Some of the most common experimental tools and resources available to yeast geneticists are presented in a way designed to engage and challenge undergraduate and graduate students eager to learn more about the experimental amenability of budding yeast. Finally, a discussion of several major discoveries derived from yeast studies highlights the far-reaching impact that the yeast system has had and will continue to have on our understanding of a variety of cellular processes relevant to all eukaryotes, including humans. PMID:24807111

Duina, Andrea A; Miller, Mary E; Keeney, Jill B

2014-05-01

297

Transcriptome analysis of Japanese pear (Pyrus pyrifolia Nakai) flower buds transitioning through endodormancy.  

PubMed

The transcriptomes of endodormant and ecodormant Japanese pear (Pyrus pyrifolia Nakai 'Kosui') flower buds were analyzed using RNA-seq technology and compared. Among de novo assembly of 114,191 unigenes, 76,995 unigenes were successfully annotated by BLAST searches against various databases. Gene Ontology (GO) enrichment analysis revealed that oxidoreductases were enriched in the molecular function category, a result consistent with previous observations of notable changes in hydrogen peroxide concentration during endodormancy release. In the GO categories related to biological process, the abundance of DNA methylation-related gene transcripts also significantly changed during endodormancy release, indicating the involvement of epigenetic regulation. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis also showed the changes in transcript abundance of genes involved in the metabolism of various phytohormones. Genes for both ABA and gibberellin biosynthesis were down-regulated, whereas the genes encoding their degradation enzymes were up-regulated during endodormancy release. In the ethylene pathway, 1-aminocyclopropane-1-carboxylate synthase (ACS), a gene encoding the rate-limiting enzyme for ethylene biosynthesis, was induced towards endodormancy release. All of these results indicated the involvement of phytohormones in endodormancy release. Furthermore, the expression of dormancy-associated MADS-box (DAM) genes was down-regulated concomitant with endodormancy release, although changes in the abundance of these gene transcripts were not as significant as those identified by transcriptome analysis. Consequently, characterization of the Japanese pear transcriptome during the transition from endormancy to ecodormancy will provide researchers with useful information for data mining and will facilitate further experiments on endodormancy especially in rosaceae fruit trees. PMID:23624675

Bai, Songling; Saito, Takanori; Sakamoto, Daisuke; Ito, Akiko; Fujii, Hiroshi; Moriguchi, Takaya

2013-07-01

298

An Experimental Investigation of NACA Submerged-Duct Entrances  

NASA Technical Reports Server (NTRS)

The results of an investigation of submerged-duct entrances are presented. It is shown that this type of entrance possesses the following characteristics: 1) very high-critical-compressibility speeds throughout the range of high-speed inlet velocity ratios; 2) very low pressure losses for the air entering the duct at all inlet-velocity ratios; and, 3) low external drag. These characteristics are obtained by the proper shaping of the contour of the upstream approach to the submerged inlets and by proper alignment of the duct lip. Design data are presented and the application of these data to a specific high-speed fighter-airplane design is discussed.

Frick, Charles W.; Davis, Wallace F.; Randall, Lauros; Mossman, Emmet A.

1945-01-01

299

Foyer and entrance details. San Bernardino Valley Union Junior College, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Foyer and entrance details. San Bernardino Valley Union Junior College, Auditorium Building. Section through foyer showing ticket window; detail front entrance with tiling; rear of ticket window. G. Stanley Wilson, Architect, A.I.A., Riverside, California. Sheet 13, job no. 692. Scale 3/4 inch to the foot. March 27, 1936. Application no. 1446, approved by the State of California, Department of Public Works, Division of Architecture, April 22, 1936. - San Bernardino Valley College, Auditorium, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

300

COPI Budding within the Golgi Stack  

PubMed Central

The Golgi serves as a hub for intracellular membrane traffic in the eukaryotic cell. Transport within the early secretory pathway, that is within the Golgi and from the Golgi to the endoplasmic reticulum, is mediated by COPI-coated vesicles. The COPI coat shares structural features with the clathrin coat, but differs in the mechanisms of cargo sorting and vesicle formation. The small GTPase Arf1 initiates coating on activation and recruits en bloc the stable heptameric protein complex coatomer that resembles the inner and the outer shells of clathrin-coated vesicles. Different binding sites exist in coatomer for membrane machinery and for the sorting of various classes of cargo proteins. During the budding of a COPI vesicle, lipids are sorted to give a liquid-disordered phase composition. For the release of a COPI-coated vesicle, coatomer and Arf cooperate to mediate membrane separation. PMID:21844168

Popoff, Vincent; Adolf, Frank; Brügger, Britta; Wieland, Felix

2011-01-01

301

Biofilm/Mat assays for budding yeast.  

PubMed

Many microbial species form biofilms/mats under nutrient-limiting conditions, and fungal pathogens rely on this social behavior for virulence. In budding yeast, mat formation is dependent on the mucin-like flocculin Flo11, which promotes cell-to-cell and cell-to-substrate adhesion in mats. The biofilm/mat assays described here allow the evaluation of the role of Flo11 in the formation of mats. Cells are grown on surfaces with different degrees of rigidity to assess their expansion and three-dimensional architecture, and the cells are also exposed to plastic surfaces to quantify their adherence. These assays are broadly applicable to studying biofilm/mat formation in microbial species. PMID:25646504

Cullen, Paul J

2015-01-01

302

Polyamines in buds of apple as affected by temperature and their relationship to bud development  

Microsoft Academic Search

The time course of changes in the concentrations of arginine and polyamines in spur buds of apple (Malus domestica Borkh.) was studied. The trees were exposed to six temperature treatments: 13° and 13°C; 13° then 20°C; 20° and 20°C; 20° then 27°C; 27° and 27°C, and 27° then 13°C in two successive periods of 6–7 and 12 weeks, starting at

L. H. Zhu; J. Tromp; A. C van de Peppel; O. Borsboom

1999-01-01

303

Genetic analysis of adaptive syndromes interrelated with seed dormancy in weedy rice (Oryza sativa).  

PubMed

Seed dormancy in rice interrelates to the weedy characteristics shattering, awn, black hull color, and red pericarp color. A cross between the weedy strain SS18-2 and the breeding line EM93-1 was developed to investigate the genetic basis and adaptive significance of these interrelationships. These characteristics or their components differed in average degree of dominance from -0.8 to 1.5, in heritability from 0.5 to 0.96, and in their contribution to phenotypic or genotypic variation in dormancy by up to 25%. Five dormancy, four shattering, and three awn-length quantitative trait loci (QTLs) were detected in the BC1 population replicated in 2 years. Two QTLs for hull color were identified, and the SS18-2-derived and EM93-1-derived alleles increased the intensity of black, and red or yellow pigmentations, respectively. The only QTL for pericarp color co-located with the red pericarp gene Rc, with the SS18-2-derived allele increasing the intensity of black and red pigmentations. Four of the five dormancy QTLs were flanked or bracketed by one to four QTLs for the interrelated characteristics. The QTL organization pattern indicates the central role of seed dormancy in adaptive syndromes for non-domesticated plants, implies that the elimination of dormancy from cultivars could arise from the selections against multiple interrelated characteristics, and challenges the use of dormancy genes at these loci in breeding varieties for resistance to pre-harvest sprouting (PHS). However, another QTL (qSD12) provides candidate gene(s) for PHS resistance because it has a large effect in the population and it is independent of the loci for interrelated characteristics. PMID:15782297

Gu, Xing-You; Kianian, Shahryar F; Hareland, Gary A; Hoffer, Barry L; Foley, Michael E

2005-04-01

304

Water deficit and induction of summer dormancy in perennial Mediterranean grasses  

PubMed Central

Background and Aims Summer dormancy is a trait conferring superior drought survival in Mediterranean perennial grasses. As the respective roles of environmental factors and water deficit on induction of summer dormancy are unclear, the effect of intense drought were tested under contrasting day lengths in a range of forage and native grasses. Methods Plants of Poa bulbosa, Dactylis glomerata ‘Kasbah’ and Lolium arundinaceum ‘Flecha’ were grown in pots (a) from winter to summer in a glasshouse and subjected to either an early or a late-spring drought period followed by a summer water deficit and (b) in controlled conditions, with long days (LD, 16 h) or short days (SD, 9 h) and either full irrigation or water deficit followed by rehydration. Leaf elongation, senescence of aerial tissues and dehydration of basal tissues were measured to assess dormancy. Endogenous abscisic acid (ABA) in basal tissues was determined by monoclonal immunoassay analysis. Key Results Even under irrigation, cessation of leaf elongation, senescence of lamina and relative dehydration of basal tissues were triggered only by a day length longer than 13 h 30 min (late spring and LD) in plants of Poa bulbosa and Dactylis glomerata ‘Kasbah’ which exhibit complete dormancy. Plants of Lolium arundinaceum ‘Flecha’ maintained leaf growth under irrigation irrespective of the day length since its dormancy is incomplete. ABA concentrations were not higher during late-spring drought than early, and could not be associated with spring dormancy induction. In summer, ABA concentration in bulbs of the desiccation-tolerant Poa were greater than in basal tissues of other species. Conclusions The results of both experiments tend to invalidate the hypothesis that water deficit has a role in early summer-dormancy induction in the range of tested grasses. However, a late-spring drought tends to increase plant senescence and ABA accumulation in basal tissues of forage grasses which could enhance summer drought survival. PMID:19369219

Volaire, Florence; Seddaiu, Giovanna; Ledda, Luigi; Lelievre, François

2009-01-01

305

Dormancy cycling and persistence of seeds in soil of a cold desert halophyte shrub  

PubMed Central

Background and Aims Formation of seed banks and dormancy cycling are well known in annual species, but not in woody species. In this study it was hypothesized that the long-lived halophytic cold desert shrub Kalidium gracile has a seed bank and dormancy cycling, which help restrict germination to a favourable time for seedling survival. Methods Fresh seeds were buried in November 2009 and exhumed and tested for germination monthly from May 2010 to December 2011 over a range of temperatures and salinities. Germination recovery and viability were determined after exposure to salinity and water stress. Seedling emergence and dynamics of the soil seed bank were investigated in the field. Key Results Seeds of K. gracile had a soil seed bank of 7030 seeds m?2 at the beginning of the growing season. About 72 % of the seeds were depleted from the soil seed bank during a growing season, and only 1·4 % of them gave rise to seedlings that germinated early enough to reach a stage of growth at which they could survive to overwinter. About 28 % of the seeds became part of a persistent soil seed bank. Buried seeds exhibited an annual non-dormancy/conditional dormancy (ND/CD) cycle, and germination varied in sensitivity to salinity during the cycle. Dormancy cycling is coordinated with seasonal environmental conditions in such a way that the seeds germinate in summer, when there is sufficient precipitation for seedling establishment. Conclusions Kalidium gracile has three life history traits that help ensure persistence at a site: a polycarpic perennial life cycle, a persistent seed bank and dormancy cycling. The annual ND/CD cycle in seeds of K. gracile contributes to seedling establishment of this species in the unpredictable desert environment and to maintenance of a persistent soil seed bank. This is the first report of a seed dormancy cycle in a cold desert shrub. PMID:24249808

Cao, Dechang; Baskin, Carol C.; Baskin, Jerry M.; Yang, Fan; Huang, Zhenying

2014-01-01

306

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

PubMed

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. PMID:25319374

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

2014-10-16

307

Quantitative trait locus analysis of tuber dormancy in diploid potato (Solanum spp.).  

PubMed

Quantitative trait locus (QTL) analysis for tuber dormancy was performed in a diploid potato population (TRP133) consisting of 110 individuals. The female parent was a hybrid between haploid S. tuberosum (2x) and S. chacoense, while the male parent was a S. phureja clone. The population was characterized for ten isozyme loci, 44 restriction fragment length polymorphisms (RFLPs) and 63 random amplified polymorphic DNAs (RAPDs). Eighty-seven of these loci segregating from the female parent were utilized to develop a linkage map that comprised 10 of the 12 chromosomes in the genome. Dormancy, as measured by days-to-sprouting after harvest, ranged from 10 to 90 days, with a mean of 19 days. QTLs were mapped by conducting one-way analyses of variance for each marker locus by dormancy combination. Twenty-two markers had a significant association with dormancy, identifying six putative QTLs localized on each of chromosomes 2, 3, 4, 5, 7 and 8. The QTL with the strongest effect on dormancy was detected on chromosome 7. A multilocus model was developed using the locus with highest R(2) value in each QTL. This model explained 57.5% of the phenotypic variation for dormancy. Seven percent of possible epistatic interactions among significant markers were significant when tested through two-way analyses of variance. When these were included in the main-effects model, it explained 72.1% of the phenotypic variation for dormancy. QTL analysis in potato, the methodology to transfer traits and interactions into the 4x level, and QTLs of value for marker-assisted selection, are discussed. PMID:24177897

Freyre, R; Warnke, S; Sosinski, B; Douches, D S

1994-10-01

308

Role of relative humidity, temperature, and water status in dormancy alleviation of sunflower seeds during dry after-ripening  

PubMed Central

The effect of various combinations of temperature and relative humidity on dormancy alleviation of sunflower seeds during dry after-ripening was investigated. The rate of dormancy alleviation depended on both temperature and embryo moisture content (MC). Below an embryo MC of 0.1 g H2O g?1 dw, dormancy release was faster at 15 °C than at higher temperatures. This suggests that dormancy release at low MC was associated with negative activation energy, supported by Arrhenius plots, and low Q10 values. At higher MC, the rate of dormancy alleviation increased with temperature, correlating well with the temperature dependence of biochemical processes. These findings suggests the involvement of two distinct cellular mechanisms in dormancy release; non-enzymatic below 0.1 g H2O g?1 dw and associated with active metabolism above this value. The effects of temperature on seed dormancy release above the threshold MC were analysed using a population-based thermal time approach and a model predicting the rate of dormancy alleviation is provided. Sunflower embryo dormancy release was effective at temperatures above 8 °C (the base temperature for after-ripening, TbAR, was 8.17 °C), and the higher the after-ripening temperature above this threshold value, the higher was the rate of dormancy loss. Thermodynamic analyses of water sorption isotherms revealed that dormancy release was associated with less bound water and increased molecular mobility within the embryonic axes but not the cotyledons. It is proposed that the changes in water binding properties result from oxidative processes and can, in turn, allow metabolic activities. PMID:20978143

Bazin, J.; Batlla, D.; Dussert, S.; El-Maarouf-Bouteau, H.; Bailly, C.

2011-01-01

309

56. View of street level entrance to parking garage elevators ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

56. View of street level entrance to parking garage elevators and detail of aluminum and glass connection to brick from east side of 1946/1948 store for homes and parking garage. - Rich's Downtown Department Store, 45 Broad Street, Atlanta, Fulton County, GA

310

2. VIEW OF WEST WALL SHOWING MAIN ENTRANCE INTO SOUTH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. VIEW OF WEST WALL SHOWING MAIN ENTRANCE INTO SOUTH LOBBY AND ALUMINUM VESTIBULE ADDED IN RECENT YEARS. ELEVATOR WILL BE CONSTRUCTED TO THE RIGHT OF THE DOORWAY IN THE NORTHWEST CORNER OF THE LOBBY. - Tillamook County Courthouse, 201 Laurel Avenue, Tillamook, Tillamook County, OR

311

4. VIEW OF THE FRONT ENTRANCE OF BUILDING 220. THROUGH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. VIEW OF THE FRONT ENTRANCE OF BUILDING 220. THROUGH THE SWINGING HARDWOOD DOUBLE DOORS AND SLIDING EXPANDED METAL/WOOD FRAMED DOORS IS THE CONTROL CENTER (LOCATED ON THE LEFT) AND BULL PEN (STRAIGHT AHEAD). - U.S. Naval Base, Pearl Harbor, Brig, Neville Way near Ninth Street at Marine Barracks, Pearl City, Honolulu County, HI

312

VIEW OF THE FRONT ENTRANCE OF BUILDING 708. THROUGH THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF THE FRONT ENTRANCE OF BUILDING 708. THROUGH THE WOODEN DOUBLE DOORS IS A CONFESSIONAL (LOCATED ON THE LEFT) AND A STAIR CASE (LOCATED ON THE RIGHT) WHICH LEADS TO THE CHOIR LOFT ABOVE. - U.S. Naval Base, Pearl Harbor, Chapel, Corner of Oakley & Nimitz Street, Pearl City, Honolulu County, HI

313

6. Interior view of main entrance vestibule looking towards lobby; ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Interior view of main entrance vestibule looking towards lobby; showing wall mounted information stations and drinking fountain; near southeast corner of building on main floor; view to north. - Ellsworth Air Force Base, Mess & Administration Building, 1561 Ellsworth Street, Blackhawk, Meade County, SD

314

1. EXTERIOR VIEW, LOOKING SOUTH, WITH SIDE FACADE AND ENTRANCE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. EXTERIOR VIEW, LOOKING SOUTH, WITH SIDE FACADE AND ENTRANCE TO THE FORMER TCI-US STEEL COMPANY BATHHOUSE FOR COLORED ORE MINERS. - Tennessee Coal & Iron-U.S. Steel Surface Plant, Company Bathhouse for Black Ore Miners, East of State Route 150 on South slope of Red Mountain, Bessemer, Jefferson County, AL

315

1. EXTERIOR VIEW, LOOKING WEST WITH FRONT FACADE AND ENTRANCE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. EXTERIOR VIEW, LOOKING WEST WITH FRONT FACADE AND ENTRANCE TO FORMER TCI-US STEEL COMPANY BATHHOUSE FOR WHITE ORE MINERS. - Tennessee Coal & Iron-U.S. Steel Surface Plant, Company Bathhouse for White Ore Miners, East of State Route 150 on South slope of Red Mountain, Bessemer, Jefferson County, AL

316

Entrance on the front of the building with canopy extending ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Entrance on the front of the building with canopy extending toward the right - Fitzsimons General Hospital, Bachelor Officers' Quarters/Officers' Club, West Harlowe Avenue, South side, 200 feet West of intersection of West Harlow Avenue & South First Street, Aurora, Adams County, CO

317

42. VIEW OF MARISCAL QUICKSILVER MINE ENTRANCE TWENTY YARDS SOUTHWEST ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

42. VIEW OF MARISCAL QUICKSILVER MINE ENTRANCE TWENTY YARDS SOUTHWEST OF MAIN SHAFT LOOKING NORTHWEST. MINE CLOSURE BY PARK SERVICE, 1995. NOTE CONCRETE FOUNDATIONS IN THE CENTER OF IMAGE BEHIND OPENING FOR MAIN-SHAFT HOIST. - Mariscal Quicksilver Mine & Reduction Works, Terlingua, Brewster County, TX

318

3. ONTARIO MINE. ADIT ENTRANCE WITH TIN ROOF. TIP TOP ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. ONTARIO MINE. ADIT ENTRANCE WITH TIN ROOF. TIP TOP IS LOCATED IN LINE WITH 'Y' BRANCH AND THE TAILING PILE FOR TIP TOP IS VISIBLE JUST TO RIGHT OF IT. CAMERA POINTED SOUTH-SOUTHEAST. - Florida Mountain Mining Sites, Ontario Mine, Northwest side of Florida Mountain, Silver City, Owyhee County, ID

319

DETAIL VIEW, MAIN ENTRANCE GATES, SHOWING A WINGED HOURGLASS MOTIF, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL VIEW, MAIN ENTRANCE GATES, SHOWING A WINGED HOURGLASS MOTIF, WHICH REFERS TO THE QUICK PASSAGE OF TIME AND THE SHORTNESS OF HUMAN LIFE. USE OF THIS MOTIF WAS A CARRYOVER FROM THE MCARTHUR GATES. - Woodlands Cemetery, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

320

7. Interior view of main entrance looking into reception space ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. Interior view of main entrance looking into reception space of wellness center offices; showing doorway to corridor accessing rehabilitation and testing facilities and small room behind; near center of west side of occupied portion; view to south. - Ellsworth Air Force Base, Mess & Administration Building, 2279 Risner Drive, Blackhawk, Meade County, SD

321

VIEW OF ENTRANCE ROAD FROM FRONT OF HOUSE. NOTE STAIRS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF ENTRANCE ROAD FROM FRONT OF HOUSE. NOTE STAIRS TO GARDEN ON LEFT, ROAD TO RIGHT, AND POMEGRANATE HEDGE AT RIGHT REAR. LOOKING SE. - Olompali State Historic Park, Mary Burdell Garden, U.S. Highway 101, Novato, Marin County, CA

322

22. View of vehicle entrance to passageway link system taken ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. View of vehicle entrance to passageway link system taken from looking west. Note DR 3 antenna in background left. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

323

6. INTERIOR VIEW OF NORTH ENTRANCE TO BASEMENT SHOWING WORKBENCH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. INTERIOR VIEW OF NORTH ENTRANCE TO BASEMENT SHOWING WORKBENCH AT PHOTO LEFT AND ONE OF TWO DOORWAYS TO MAIN BASEMENT AREA AT PHOTO RIGHT. VIEW TO NORTH. - Bishop Creek Hydroelectric System, Control Station, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

324

Alternative Graduation and Entrance Requirements: A Human Essential.  

ERIC Educational Resources Information Center

Recently, state government and concerned educational agencies in California have shown much interest in adopting a more "rigorous" curriculum for all students, longer school days, and stricter high school graduation and college entrance requirements. These proposed measures are not wrong in themselves, but as standards required for every student…

Glines, Don

325

West wing. Sidewalk streetscape shows art deco entrance door to ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

West wing. Sidewalk streetscape shows art deco entrance door to service yard and access ramp (added ca. 1985) along the south façade of the west wing. - Jewish Community Center of San Francisco, 3200 California Street, San Francisco, San Francisco County, CA

326

UW China Hong Kong Entrance Scholarship University of Waterloo ID#  

E-print Network

UW ­ China Hong Kong Entrance Scholarship Name: University of Waterloo ID#: Program Applied of Waterloo who currently lives in or who previously lived in Hong Kong or mainland China. Candidates must also intend to return to Hong Kong or China after graduation. Selection will be based on academic

Le Roy, Robert J.

327

15. View of rear entrance and yard at west end ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. View of rear entrance and yard at west end of Building E-1, facing west towards Luckie Street. Replicates historic view at GA-2309-5. - Clark Howell Homes (Public Housing), Bounded by North Avenue, Lovejoy Street, Mills Street & Luckie Street, Atlanta, Fulton County, GA

328

2. WEST FRONT ENTRANCE, WITH OWNERS MR. & MRS. ISACC ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. WEST FRONT ENTRANCE, WITH OWNERS MR. & MRS. ISACC N. HAGAN (WHO CONTRACTED WITH FRANK LLOYD WRIGHT FOR THE DESIGN OF THIS HOUSE) - Isaac N. Hagan House, Kentuck Knob, U.S. Route 40 vicinity (Stewart Township), Chalkhill, Fayette County, PA

329

View looking northeast to the "parts and service entrance" and ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View looking northeast to the "parts and service entrance" and to the porte cochere connecting the showroom to the service area; note windows for what appears to be office space above - Bob Peck Chevrolet, 800 North Glebe Road, Arlington, Arlington County, VA

330

"Dog House" or vestibule at the secondstory entrance located at ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

"Dog House" or vestibule at the second-story entrance located at the intersection of the west Verandah of the south wing and the south Verandah of the rotunda extension. - U. S. Naval Asylum, Biddle Hall, Gray's Ferry Avenue, Philadelphia, Philadelphia County, PA

331

PRIMARY ENTRANCE INTO THE JENNE FARM, WEST FAÇADE. (The Jenne ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PRIMARY ENTRANCE INTO THE JENNE FARM, WEST FAÇADE. (The Jenne Barn has board and batten exterior cladding and sits above-grade on a poured concrete foundation. The barn is painted red with white trim. This door is painted green.) - Jenne Farm, Barn, 538 Engle Road, Coupeville, Island County, WA

332

View of entrance tunnel outside Portal elevator. Tunnel ahead to ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of entrance tunnel outside Portal elevator. Tunnel ahead to Control Center, right to Launchers, left to Antenna Silos - Titan One Missile Complex 2A, .3 miles west of 129 Road and 1.5 miles north of County Line Road, Aurora, Adams County, CO

333

ENTRANCE TO GOLD AREA SECURITY ROOM IN BASEMENT, LOCATED IN ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ENTRANCE TO GOLD AREA SECURITY ROOM IN BASEMENT, LOCATED IN BOTTOM OF ORIGINAL WET-BUCKET ELEVATOR SHAFT, ADJACENT TO DIESTER TABLE ROOM. NOTE BOARD WITH INDIVIDUAL TAGS FOR GOLD AREA EMPLOYEES. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

334

5. PERSPECTIVE VIEW TO THE NORTHWEST SHOWING ENTRANCE TO CREW ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. PERSPECTIVE VIEW TO THE NORTHWEST SHOWING ENTRANCE TO CREW SHELTER AND THE TAPERING SHAPE OF THE SOUTHEAST END WALL OF AR-8. - Edwards Air Force Base, South Base, Rammed Earth Aircraft Dispersal Revetments, Western Shore of Rogers Dry Lake, Boron, Kern County, CA

335

View of main entrance of the Church of God. This ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of main entrance of the Church of God. This structure was originally a lodge hall for the Woodmen of the World from the adjacent mill neighborhoods such as Lincoln and Dallas Mill - 601 Humes Avenue (House), 601 Humes Avenue, Huntsville, Madison County, AL

336

The Cognitive Abilities of Children: Reflections from an Entrance Exam  

ERIC Educational Resources Information Center

The basic determiner for the school in which the children who completed their primary education will in at an upper education level in Turkey is the entrance exam carried out nationwide. The items of national exam, called as LDE (Level Determination Exam) which the primary education pupils (aged between 12 and 15) will participate in Turkey were…

Cil, Emine; Cepni, Salih

2012-01-01

337

Perspective of Great Stone Arch entrance to Fort Tryon Park ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Perspective of Great Stone Arch entrance to Fort Tryon Park from HHP northbound, carrying Margaret Corbin Drive, looking south. - Henry Hudson Parkway, Extending 11.2 miles from West 72nd Street to Bronx-Westchester border, New York, New York County, NY

338

Getting Interpersonal on a University Entrance Exam Impromptu Writing Task  

ERIC Educational Resources Information Center

This article explores the types of audience engagement strategies used by a Japanese secondary school student in an after school course preparing for a high-stakes impromptu academic writing task on a university entrance exam. The study uses appraisal theory--the branch of Systemic Functional Linguistics (SFL) concerned with the patterning of…

Myskow, Gordon; Gordon, Kana

2012-01-01

339

A real time talking port entrance current monitoring system  

Microsoft Academic Search

The currents at the entrance to Port Everglades, Florida are strong, variable, and unpredictable. This project was undertaken to provide additional information to the port's pilots about the currents at this location, so that they may continue to safely guide ships to and from Port Everglades. A major goal of the system's design was to optimize the usefulness of the

A. P. Shefter; B. L. Grose

1996-01-01

340

OVERVIEW OF ARENA AND SOUTHWEST ENTRANCE TERRACE SHOWING THE PROXIMITY ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OVERVIEW OF ARENA AND SOUTHWEST ENTRANCE TERRACE SHOWING THE PROXIMITY OF THE UNDERGROUND SPLINTERPROOF SHELTER, FACILITY S897 (CENTER) TO THE ARENA. VIEW FACING NORTHEAST - U.S. Naval Base, Pearl Harbor, Bloch Recreation Center & Arena, Between Center Drive & North Road near Nimitz Gate, Pearl City, Honolulu County, HI

341

3. West end. Note arched basement entrance at north half ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. West end. Note arched basement entrance at north half of west endwall. Sand tower (MN-99-E) at right. View to east. - Duluth & Iron Range Rail Road Company Shops, Oil House, Southwest of downtown Two Harbors, northwest of Agate Bay, Two Harbors, Lake County, MN

342

View of the main entrance with basrelief limestone panel designed ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View of the main entrance with bas-relief limestone panel designed by C. Paul Jennwein upon which is inscribed "Lege Atque Ordine Omnia Fiunt" (translated as by law and order all is accomplished) - United States Department of Justice, Constitution Avenue between Ninth & Tenth Streets, Northwest, Washington, District of Columbia, DC

343

Interior view, front entrance doors; note; double doors have a ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Interior view, front entrance doors; note; double doors have a box lock, sliding bolt locks into door head and sill as well as modern locks, butt hinges, slightly recessed panels, and five-ligh transom - Fort Hill, Clemson University Campus, Clemson, Pickens County, SC

344

3. Interior. Looking from balance room to the front entrance. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. Interior. Looking from balance room to the front entrance. Chemicals related to Edison's experiments on the extraction of latex for rubber from the goldenrod plant. Room is set up based on reconstruction research done in 1972. - Thomas A. Edison Laboratories, Building No. 2, West Orange, Essex County, NJ

345

1. OVERVIEW OF MAIN ENTRANCE TO RESORT WITH STATE HIGHWAY ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. OVERVIEW OF MAIN ENTRANCE TO RESORT WITH STATE HIGHWAY 89 IN FOREGROUND; MAIN LODGE IS ON THE FAR LEFT (WEST); CORD CABIN IS BEHIND AND TO THE RIGHT OF PARKED VEHICLES. - Camp Richardson Resort, Cord Cabin, U.S. Highway 89, 3 miles west of State Highway 50 & 89, South Lake Tahoe, El Dorado County, CA

346

31. SE CORNER OF MAIN ENTRANCE STAIRWAY IN EAST FACADELEVEL, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. SE CORNER OF MAIN ENTRANCE STAIRWAY IN EAST FACADE--LEVEL, ANGLED NORMAL ANGLE Copy photograph of photogrammetric plate LC-HABS-FS13-B-1974-830R. - St. Mary's Seminary, 600 North Paca Street, Baltimore, Independent City, MD

347

32. NE CORNER OF MAIN ENTRANCE STAIRWAY IN EAST FACADELEVEL, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. NE CORNER OF MAIN ENTRANCE STAIRWAY IN EAST FACADE--LEVEL, ANGLED NORMAL ANGLE Copy photograph of photogrammetric plate LC-HABS-FS13-B-1974-831L. - St. Mary's Seminary, 600 North Paca Street, Baltimore, Independent City, MD

348

30. BASEMENT WINDOW AND GRILLE SOUTH OF MAIN ENTRANCE IN ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. BASEMENT WINDOW AND GRILLE SOUTH OF MAIN ENTRANCE IN EAST FACADE--LEVEL, FRONTAL NORMAL ANGLE Copy photograph of photogrammetric plate LC-HABS-FS13-B-1974-829R. - St. Mary's Seminary, 600 North Paca Street, Baltimore, Independent City, MD

349

9. VIEW TO SOUTH SHOWING ENTRANCES TO BUILDING AT NORTHEAST ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. VIEW TO SOUTH SHOWING ENTRANCES TO BUILDING AT NORTHEAST CORNER. DOORS TO LEFT WERE FOR INTERIOR RAILROAD SPUR. ROLL-UP GARAGE DOOR TO RIGHT HAS REPLACED ORIGINAL PEDESTRIAN DOORS WHERE HOURLY SHIP WORKERS REPORTED TO WORK. - Rosie the Riveter National Historical Park, Ford Assembly Plant, 1400 Harbour Way South, Richmond, Contra Costa County, CA

350

21. VIEW OF THE ENTRANCE TO THE TUNNEL CONNECTING BUILDINGS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. VIEW OF THE ENTRANCE TO THE TUNNEL CONNECTING BUILDINGS 881 AND 883. THE TUNNEL WAS CONSTRUCTED IN 1957 TO TRANSPORT ENRICHED URANIUM COMPONENTS BETWEEN THE BUILDINGS. (1/98) - Rocky Flats Plant, General Manufacturing, Support, Records-Central Computing, Southern portion of Plant, Golden, Jefferson County, CO

351

A proposed mechanism for physical dormancy break in seeds of Ipomoea lacunosa (Convolvulaceae)  

PubMed Central

Background and Aims The water-impermeable seeds of Ipomoea lacunosa undergo sensitivity cycling to dormancy breaking treatment, and slits are formed around bulges adjacent to the micropyle during dormancy break, i.e. the water gap opens. The primary aim of this research was to identify the mechanism of slit formation in seeds of this species. Methods Sensitive seeds were incubated at various combinations of relative humidity (RH) and temperature after blocking the hilar area in different places. Increase in seed mass was measured before and after incubation. Scanning electron microscopy (SEM) and staining of insensitive and sensitive seeds were carried out to characterize these states morphologically and anatomically. Water absorption was monitored at 35 and 25 °C at 100 % RH. Key Results There was a significant relationship between incubation temperature and RH with percentage seed dormancy break. Sensitive seeds absorbed water vapour, but insensitive seeds did not. Different amounts of water were absorbed by seeds with different blocking treatments. There was a significant relationship between dormancy break and the amount of water absorbed during incubation. Conclusions Water vapour seals openings that allow it to escape from seeds and causes pressure to develop below the bulge, thereby causing slits to form. A model for the mechanism of formation of slits (physical dormancy break) is proposed. PMID:19098068

Jayasuriya, K. M. G. Gehan; Baskin, Jerry M.; Geneve, Robert L.; Baskin, Carol C.

2009-01-01

352

[Effects of photoperiod on photosynthesis and PSII performance in peach during dormancy induction].  

PubMed

Long-day and short-day photoperiods were set artificially, with natural condition as the control, to examine photosynthetic parameters and chlorophyll fluorescence transient kinetics of 6-year-old 'Chunjie' peach cultivar (Prunus persica cv. Chunjie), and to investigate the effects of photoperiod on photosynthesis of the northern deciduous fruit trees. The tree advanced into the dormancy induction period under the short-day condition, and delayed under the long-day condition. In the dormancy induction period, the leaf net photosynthetic rate (Pn) and stomatal conductance (g(s)) decreased, and the intercellular CO2 concentration (Ci) increased, suggesting that the Pn decreased because of non-stomatal limitation. Maximum quantum yield for primary photochemistry (PhiPo, or Fv/Fm), potential activity (Fv/Fo), probability that a trapped exciton moved an electron into the electron transport chain beyond Q(A)-(Psi(o)) and performance index on absorption basis (Pl(ABS)) decreased in the dormancy induction period, suggesting that the electron transport capacity of photosynthetic electron transport chain was inhibited, possibly due to the damage to downstream electron transport chain (after Q(A)- acceptor) of PS II reaction center. Long-day photoperiod improved Pn in the dormancy induction period, and reduced the range of decline in PI(ABS) and the injured degree of photosystem. Short-day photoperiod deepened and accelerated the damage to photosynthetic apparatus significantly. The induced effect of photoperiod was associated with the dormancy processes. PMID:25345042

Li, Dong-Mei; Tan, Qiu-Ping; Gao, Dong-Sheng; Chen, Xiu-De; Li, Ling

2014-07-01

353

Molecular cloning of Sdr4, a regulator involved in seed dormancy and domestication of rice.  

PubMed

Seed dormancy provides a strategy for flowering plants to survive adverse natural conditions. It is also an important agronomic trait affecting grain yield, quality, and processing performance. We cloned a rice quantitative trait locus, Sdr4, which contributes substantially to differences in seed dormancy between japonica (Nipponbare) and indica (Kasalath) cultivars. Sdr4 expression is positively regulated by OsVP1, a global regulator of seed maturation, and in turn positively regulates potential regulators of seed dormancy and represses the expression of postgerminative genes, suggesting that Sdr4 acts as an intermediate regulator of dormancy in the seed maturation program. Japonica cultivars have only the Nipponbare allele (Sdr4-n), which endows reduced dormancy, whereas both the Kasalath allele (Srd4-k) and Sdr4-n are widely distributed in the indica group, indicating prevalent introgression. Srd4-k also is found in the wild ancestor Oryza rufipogon, whereas Sdr4-n appears to have been produced through at least two mutation events from the closest O. rufipogon allele among the accessions examined. These results are discussed with respect to possible selection of the allele during the domestication process. PMID:20220098

Sugimoto, Kazuhiko; Takeuchi, Yoshinobu; Ebana, Kaworu; Miyao, Akio; Hirochika, Hirohiko; Hara, Naho; Ishiyama, Kanako; Kobayashi, Masatomo; Ban, Yoshinori; Hattori, Tsukaho; Yano, Masahiro

2010-03-30

354

Influence of the Testa on Seed Dormancy, Germination, and Longevity in Arabidopsis1  

PubMed Central

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 the testa in the model plant Arabidopsis, we compared mutants affected in testa pigmentation and/or structure for dormancy, germination, and storability. The seeds of most mutants exhibited reduced dormancy. Moreover, unlike wild-type testas, mutant testas were permeable to tetrazolium salts. These altered dormancy and tetrazolium uptake properties were related to defects in the pigmentation of the endothelium and its neighboring crushed parenchymatic layers, as determined by vanillin staining and microscopic observations. Structural aberrations such as missing layers or a modified epidermal layer in specific mutants also affected dormancy levels and permeability to tetrazolium. Both structural and pigmentation mutants deteriorated faster than the wild types during natural aging at room temperature, with structural mutants being the most strongly affected. PMID:10677433

Debeaujon, Isabelle; Léon-Kloosterziel, Karen M.; Koornneef, Maarten

2000-01-01

355

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

Microsoft Academic Search

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

Tomasz A Paw?owski

2009-01-01

356

Cross-species approaches to seed dormancy and germination: conservation and biodiversity of ABA-regulated mechanisms  

E-print Network

Cross-species approaches to seed dormancy and germination: conservation and biodiversity of ABA OF GERMINATION 1), a major quantitative trait gene more specifically involved in seed dormancy, was so far only- dormant seeds was not known. Seed germination of Lepi- dium sativum (`garden cress') is controlled by ABA

Leubner, Gerhard

357

Seed dormancy and germination: the role of abscisic acid and gibberellins and the importance of hormone mutants  

Microsoft Academic Search

Over the past decades many studies have aimed at elucidating the regulation of seed dormancy and germination. Many hypotheses have been proposed and rejected but the regulatory principle behind changes in dormancy and induction of germination is still a ‘black’ box. The majority of proposed mechanisms have a role for certain plant hormones in common. Abscisic acid and the gibberellins

H. W. M. Hilhorst; C. M. Karssen

1992-01-01

358

Budding and fruitfulness of seedless grape in the São Francisco River Valley, northeast Brazil  

Microsoft Academic Search

th 2002, and Apr 8 th to 12 th 2002. The bud burst percentage was calculated by the ratio number of pushed buds and the total number of buds. The fertility index was obtained by dividing the total number of bunches by the total number of buds per plant. The results were statistically analyzed by the SAS computer program, and

Patrícia Coelho de S. Leão; Emanuel E. G da Silva

359

Viral and host proteins that modulate filovirus budding  

PubMed Central

The filoviruses, Ebola and Marburg, utilize a multifaceted mechanism for assembly and budding of infectious virions from mammalian cells. Growing evidence not only demonstrates the importance of multiple viral proteins for efficient assembly and budding, but also the exploitation of various host proteins/pathways by the virus during this late stage of filovirus replication, including endocytic compartments, vacuolar protein sorting pathways, ubiquitination machinery, lipid rafts and cytoskeletal components. Continued elucidation of these complex and orchestrated virus-host interactions will provide a fundamental understanding of the molecular mechanisms of filovirus assembly/budding and ultimately lead to the development of novel viral- and/or host-oriented therapeutics to inhibit filovirus egress and spread. This article will focus on the most recent studies on host interactions and modulation of filovirus budding and summarize the key findings from these investigations. PMID:20730024

Liu, Yuliang; Harty, Ronald N

2010-01-01

360

Dissecting the spatial structure of overlapping transcription in budding yeast  

E-print Network

This thesis presents a computational and algorithmic method for the analysis of high-resolution transcription data in the budding yeast Saccharomyces cerevisiae. We begin by describing a computational system for storing ...

Danford, Timothy W. (Timothy William), 1979-

2010-01-01

361

Grapevine bud break prediction for cool winter climates  

NASA Astrophysics Data System (ADS)

Statistical analysis of bud break data for grapevine ( Vitis vinifera L. cvs. Riesling and Müller-Thurgau) at 13 sites along the northern boundary of commercial grapevine production in Europe revealed that, for all investigated sites, the heat summation method for bud break prediction can be improved if the starting date for the accumulation of heat units is specifically determined. Using the coefficient of variance as a criterion, a global minimum for each site can be identified, marking the optimum starting date. Furthermore, it was shown that the application of a threshold temperature for the heat summation method does not lead to an improved prediction of bud break. Using site-specific parameters, bud break of grapevine can be predicted with an accuracy of ± 2.5 days. Using average parameters, the prediction accuracy is reduced to ± 4.5 days, highlighting the sensitivity of the heat summation method to the quality and the representativeness of the driving temperature data.

Nendel, Claas

2010-05-01

362

Studies on Cytokinin-Controlled Bud Formation in Moss Protonemata  

PubMed Central

Application of cytokinins to moss protonemata of the proper physiological age causes bud formation on specific cells (caulonema). During the early stages of their development, buds revert to protonemal filaments if the cytokinin has been removed by washing the protonemata. This indicates that the hormone is not acting as a “trigger” but has to be present during a critical period of time until differentiation is stabilized. Autoradiographs of protonemata treated with a labeled cytokinin, benzyladenine-benzyl-7-14C, show a striking accumulation of the radioactivity in caulonema cells which are in the stage of bud formation, and in the buds themselves. Cells which did not react to the hormone contained very little radioactivity. The accumulation of benzyladenine in the “target cells” may be due to the presence of binding sites which, in turn, may distinguish responding cells from non-responding ones. Images PMID:16656847

Brandes, H.; Kende, H.

1968-01-01

363

Isolation of Glucanase-Containing Particles from Budding Saccharomyces cerevisiae  

Microsoft Academic Search

In an investigation of the role of glucanases in modifying yeast cell walls at the location of new buds, vesicles derived from the endoplasmic reticulum, which are secreted locally into the cell wall of growing buds and may be involved in the secretion of glucanases, have been isolated. In yeast, exo-beta -1,3-glucanase (EC 3.2.1.6) is present both extra- and intracellularly.

P. Matile; M. Cortat; A. Wiemken; A. Frey-Wyssling

1971-01-01

364

Complex Combination of Seed Dormancy and Seedling Development Determine Emergence of Viburnum tinus (Caprifoliaceae)  

PubMed Central

• Background and Aims The shrub Viburnum tinus is widely distributed in mattoral vegetation of the Mediterranean basin. The purpose of the present study was to classify the seed dormancy type and examine the requirements for embryo growth, root protrusion and shoot emergence. • Methods Overwintered fruits were collected in western Spain in April 2001 and prepared in three ways: entire pericarp was removed, exocarp and mesocarp were removed or fruits were left intact. Fruits treated in these three ways were subjected to artificial annual temperature cycles or to constant temperature regimes for 1·5 years. • Key Results Removal of exocarp and mesocarp was necessary for embryo growth and germination. High temperature favoured dormancy alleviation and embryo growth, intermediate to low temperatures favoured root protrusion, and intermediate temperature shoot emergence. There was substantial germination at constant temperature regimes, indicating an overlap between temperature intervals suitable for the different stages of embryo and seedling development. Functionally, V. tinus has the same root and shoot emergence pattern that is described for other Viburnum species considered to have epicotyl dormancy. However, the requirement for high and low temperatures for radicle protrusion and epicotyl emergence, respectively, was missing in V. tinus; these characters are the foundation for the epicotyl dormancy classification. • Conclusions It is concluded that V. tinus does not have epicotyl dormancy. Instead, there is a combination of a weak morphophysiological dormancy and a slow germination process, where different temperatures during an annual cycle favour different development stages. The present study suggests that the first complete seedlings would emerge in the field 1·5 years after fruit maturation in October, i.e. seed dispersal during winter, embryo growth during the first summer, root protrusion and establishment during the second autumn and winter, and cotyledon emergence during the second spring. PMID:15546926

KARLSSON, LAILA M.; HIDAYATI, SITI N.; WALCK, JEFFREY L.; MILBERG, PER

2004-01-01

365

Poliovirus Infection Transiently Increases COPII Vesicle Budding  

PubMed Central

Poliovirus (PV) requires membranes of the host cell's secretory pathway to generate replication complexes (RCs) for viral RNA synthesis. Recent work identified the intermediate compartment and the Golgi apparatus as the precursors of the replication “organelles” of PV (N. Y. Hsu et al., Cell 141:799–811, 2010). In this study, we examined the effect of PV on COPII vesicles, the secretory cargo carriers that bud from the endoplasmic reticulum and homotypically fuse to form the intermediate compartment that matures into the Golgi apparatus. We found that infection by PV results in a biphasic change in functional COPII vesicle biogenesis in cells, with an early enhancement and subsequent inhibition. Concomitant with the early increase in COPII vesicle formation, we found an increase in the membrane fraction of Sec16A, a key regulator of COPII vesicle formation. We suggest that the early burst in COPII vesicle formation detected benefits PV by increasing the precursor pool required for the formation of its RCs. PMID:22740409

Trahey, Meg; Oh, Hyung Suk; Cameron, Craig E.

2012-01-01

366

33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...  

Code of Federal Regulations, 2012 CFR

...Bay Entrance Channel, Humboldt Bay, California. 165.1195 Section 165.1195...Bay Entrance Channel, Humboldt Bay, California. (a) Location. The Regulated...Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in...

2012-07-01

367

33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...  

Code of Federal Regulations, 2011 CFR

...Bay Entrance Channel, Humboldt Bay, California. 165.1195 Section 165.1195...Bay Entrance Channel, Humboldt Bay, California. (a) Location. The Regulated...Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in...

2011-07-01

368

33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...  

Code of Federal Regulations, 2010 CFR

...Bay Entrance Channel, Humboldt Bay, California. 165.1195 Section 165.1195...Bay Entrance Channel, Humboldt Bay, California. (a) Location. The Regulated...Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in...

2010-07-01

369

33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...  

Code of Federal Regulations, 2013 CFR

...Bay Entrance Channel, Humboldt Bay, California. 165.1195 Section 165.1195...Bay Entrance Channel, Humboldt Bay, California. (a) Location. The Regulated...Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in...

2013-07-01

370

33 CFR 165.1195 - Regulated Navigation Area; Humboldt Bay Bar Channel and Humboldt Bay Entrance Channel, Humboldt...  

Code of Federal Regulations, 2014 CFR

...Bay Entrance Channel, Humboldt Bay, California. 165.1195 Section 165.1195...Bay Entrance Channel, Humboldt Bay, California. (a) Location. The Regulated...Bay Entrance Channel, Humboldt Bay, California. (b) Definitions. As used in...

2014-07-01

371

Information on Entrance Examination (2011 Academic Year) Special Selection for Applicants with Overseas Education, Schedule B  

E-print Network

Information on Entrance Examination (2011 Academic Year) Special Selection for Applicants to the entrance examination and to write the essay on another (but same size) answer sheet at the entrance equivalent hereafter). Questions and answers about his/her master degree thesis, knowledge as a graduate

Yamamoto, Hirosuke

372

2. View from the mansion formal entrance driveway toward the ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. View from the mansion formal entrance driveway toward the big meadow at the Billings Farm & Museum. The driveway is flanked by granite gateposts surmounted by wrought iron urn lamps. The view includes a manicured hemlock hedge (Tsuga canadensis) retained by a stone wall at left, and white birch (Betula species) under-planted with ferns at center. - Marsh-Billings-Rockefeller National Historical Park, 54 Elm Street, Woodstock, Windsor County, VT

373

GENERAL VIEW, MAIN ENTRANCE GATES, LOOKING SOUTH ACROSS WOODLANDS AVENUE. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GENERAL VIEW, MAIN ENTRANCE GATES, LOOKING SOUTH ACROSS WOODLANDS AVENUE. IN 1933, A CITY OF PHILADELPHIA LAND CONDEMNATION REQUIRED THE DEMOLITION OF AN EXISTING GATEWAY COMPLETED IN 1857 ON PLANS BY JOHN MCARTHUR, JR. PAUL CRET DESIGNED THE NEW GATES IN 1936. THEY WERE COMPLETED THE FOLLOWING YEAR AND MOVED TO THEIR PRESENT LOCATION IN 1948 AFTER ANOTHER CITY LAND CONDEMNATION. - Woodlands Cemetery, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

374

Elevation and plan of main entrance. San Bernardino Valley Union ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Elevation and plan of main entrance. San Bernardino Valley Union Junior College, Library Building. Also includes full size detail of mullion for iron gates. Howard E. Jones, Architect, San Bernardino, California. Sheet 5, job no. 315. Scale 1/2 inch to the foot. No date given on sheet (probably March or April, 1927). - San Bernardino Valley College, Library, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

375

Details of main entrance. San Bernardino Valley Union Junior College, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Details of main entrance. San Bernardino Valley Union Junior College, Classics Building. Half elevation of exterior iron gates, half plan of interior with tiling, and section AA. Howard E. Jones, Architect, San Bernardino, California. Sheet 5, job no. 312. Scale 1/2 inch to the foot. February 15, 1927. - San Bernardino Valley College, Classics Building, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA

376

19. PRIVATE SIDE ENTRANCE ADDED IN 1921 TO GIVE BARRIERFREE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. PRIVATE SIDE ENTRANCE ADDED IN 1921 TO GIVE BARRIER-FREE ACCESS FROM THE DRIVEWAY TO THE ELEVATOR. Wrought iron railings, extended upper step of stoop (indicated by the darker concrete between the two vertical posts), and wooden ramp added by the National Trust to meet modern barrier-free access codes, circa 1980. - Woodrow Wilson House, 2340 South S Street, Northwest, Washington, District of Columbia, DC

377

Viscoelastic Modelling of Entrance Flow Using Multimode Leonov Model  

NASA Astrophysics Data System (ADS)

A simulation of planar 2D flow of a viscoelastic fluid employing the Leonov constitutive equation has been presented. Triangular finite elements with lower-order interpolations have been employed for velocity and pressure as well as the extra stress tensor arising from the constitutive equation. A generalized Lesaint-Raviart method has been used for an upwind discretization of the material derivative of the extra stress tensor in the constitutive equation. The upwind scheme has been further strengthened in our code by also introducing a non-consistent streamline upwind Petrov-Galerkin method to modify the weighting function of the material derivative term in the variational form of the constitutive equation. A variational equation for configurational incompressibility of the Leonov model has also been satisfied explicitly.The corresponding software has been used to simulate planar 2D entrance flow for a 4:1 abrupt contraction up to a Deborah number of 670 (Weissenberg number of 6.71) for a rubber compound using a three-mode Leonov model. The predicted entrance loss is found to be in good agreement with experimental results from the literature. Corresponding comparisons for a commercial-grade polystyrene, however, indicate that the predicted entrance loss is low by a factor of about four, indicating a need for further investigation.

Gupta, Mahesh; Hieber, C. A.; Wang, K. K.

1997-03-01

378

Seed dormancy and germination in three Crocus ser. Verni species (Iridaceae): implications for evolution of dormancy within the genus.  

PubMed

The aim of this work was to examine whether seed ecophysiological traits in three closely related Crocus species were associated with ecological niche differentiation and species divergence. Seeds of the temperate tetraploid cytotype of Crocus neapolitanus, the sub-Mediterranean C. etruscus and the Mediterranean C. ilvensis were placed either on agar in the laboratory under different periods of simulated seasonal conditions or in nylon mesh bags buried outdoors to examine embryo growth, radicle and shoot emergence. In agreement with the phenology observed outdoors, in the laboratory embryos required a cool temperature (ca. 10 °C) to grow to full size (embryo length:seed length, E:S ratio ca. 0.75) but only after seeds received a warm stratification; radicle emergence then followed immediately (November). Shoot emergence is a temporally separated phase (March) that was promoted by cold stratification in C. neapolitanus while in the other two species this time lag was attributed to a slow continuous developmental process. These species have similar embryo growth and radicle phenology but differ in their degree of epicotyl dormancy, which is related to the length of local winter. Conclusions from laboratory experiments that only consider root emergence could be misleading; evaluating the phenology of both root and shoot emergence should be considered in order to demonstrate ecologically meaningful differences in germination behaviour and to develop effective propagation protocols. Although these taxa resulted from recent speciation processes, the outcomes suggest an early onset of adaptation to local ecological factors and that phylogeny may represent a significant constraint in the evolution and expression of seed traits in Crocus. PMID:24533601

Carta, A; Probert, R; Moretti, M; Peruzzi, L; Bedini, G

2014-11-01

379

Seed Dormancy and Germination of the European Chaerophyllum temulum (Apiaceae), a Member of a Trans-Atlantic Genus  

PubMed Central

Background and Aims The European Chaerophyllum temulum and two North American Chaerophyllum species have a trans-Atlantic disjunct distribution. This work aimed to resolve requirements for dormancy break and germination of C. temulum seeds and to compare dormancy traits with those of the two North American congeners. Methods Phenology of germination and embryo growth was studied by regularly exhuming seeds sown in natural conditions. Temperature requirements for embryo growth, breaking of dormancy and germination were determined by incubating seeds under controlled laboratory conditions. Additionally the effect of GA3 on germination was tested to determine the specific dormancy type. Key Results In natural conditions, embryo growth starts in early winter. Seedlings emerge in late winter shortly after the embryos reached the critical ratio for embryo length to seed length (E : S) of approx. 0·95. Growth of the embryo only occurs during a prolonged incubation period at 5 °C. After stratification at 5 °C, which breaks physiological and morphological dormancy, seeds can germinate at a wide range of temperatures. GA3 did not substitute for cold stratification in seeds placed at 23 °C. Conclusions Chaerophyllum temulum has deep complex morphophysiological dormancy. This dormancy type differs considerably from that of the two North American congeners. PMID:17556382

Vandelook, Filip; Bolle, Nele; Van Assche, Jozef A.

2007-01-01

380

Physiology, morphology and phenology of seed dormancy break and germination in the endemic Iberian species Narcissus hispanicus (Amaryllidaceae)  

PubMed Central

Background and Aims Only very few studies have been carried out on seed dormancy/germination in the large monocot genus Narcissus. A primary aim of this study was to determine the kind of seed dormancy in Narcissus hispanicus and relate the dormancy breaking and germination requirements to the field situation. Methods Embryo growth, radicle emergence and shoot growth were studied by subjecting seeds with and without an emerged radicle to different periods of warm, cold or warm plus cold in natural temperatures outdoors and under controlled laboratory conditions. Key Results Mean embryo length in fresh seeds was approx. 1·31 mm, and embryos had to grow to 2·21 mm before radicle emergence. Embryos grew to full size and seeds germinated (radicles emerged) when they were warm stratified for 90 d and then incubated at cool temperatures for 30 d. However, the embryos grew only a little and no seeds germinated when they were incubated at 9/5, 10 or 15/4 °C for 30 d following a moist cold pre-treatment at 5, 9/5 or 10 °C. In the natural habitat of N. hispanicus, seeds are dispersed in late May, the embryo elongates in autumn and radicles emerge (seeds germinate) in early November; however, if the seeds are exposed to low temperatures before embryo growth is completed, they re-enter dormancy (secondary dormancy). The shoot does not emerge until March, after germinated seeds are cold stratified in winter. Conclusion Seeds of N. hispanicus have deep simple epicotyl morphophysiological dormancy (MPD), with the dormancy formula C1bB(root) – C3(epicotyl). This is the first study on seeds with simple MPD to show that embryos in advanced stages of growth can re-enter dormancy (secondary dormancy). PMID:21335326

Copete, Elena; Herranz, José M.; Ferrandis, Pablo; Baskin, Carol C.; Baskin, Jerry M.

2011-01-01

381

Natural Variation for Seed Longevity and Seed Dormancy Are Negatively Correlated in Arabidopsis1[W][OA  

PubMed Central

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 and seed longevity described as two traits. Seed dormancy is defined as a temporary failure of a viable seed to germinate in conditions that favor germination, whereas seed longevity is defined as seed viability after dry storage (storability). In plants, the association of seed longevity with seed dormancy has not been studied in detail. This is surprising given the ecological, agronomical, and economic importance of seed longevity. We studied seed longevity to reveal its genetic regulators and its association with seed dormancy in Arabidopsis (Arabidopsis thaliana). Integrated quantitative trait locus analyses for seed longevity, in six recombinant inbred line populations, revealed five loci: Germination Ability After Storage1 (GAAS1) to GAAS5. GAAS loci colocated with seed dormancy loci, Delay Of Germination (DOG), earlier identified in the same six recombinant inbred line populations. Both GAAS loci and their colocation with DOG loci were validated by near isogenic lines. A negative correlation was observed, deep seed dormancy correlating with low seed longevity and vice versa. Detailed analysis on the collocating GAAS5 and DOG1 quantitative trait loci revealed that the DOG1-Cape Verde Islands allele both reduces seed longevity and increases seed dormancy. To our knowledge, this study is the first to report a negative correlation between seed longevity and seed dormancy. PMID:23085841

Nguyen, Thu-Phuong; Keizer, Paul; van Eeuwijk, Fred; Smeekens, Sjef; Bentsink, Leónie

2012-01-01

382

The Mode of Origin of Root Buds and Root Sprouts in the Clonal Tree Sassafras albidum (Lauraceae)  

Microsoft Academic Search

The developmental anatomy of root buds and root sprouts was examined in the clonal tree Sassafras albidum. Root samples from 13 clones that varied widely in age and vigor were sectioned and two types of buds were found, ''additional'' buds and ''reparative'' buds. Additional buds form during the early growth of uninjured roots and they perennate by growing outwards in

Michael J. Bosela; Frank W. Ewers

1997-01-01

383

Seed Dormancy and Delayed Flowering in Monocarpic Plants: Selective Interactions in a Stochastic Environment  

Microsoft Academic Search

We explore the effects of temporal variation in multiple demographic rates on the joint evolution of delayed reproduction and seed dormancy using integral projection models (IPMs). To do this, we extend the standard IPM to include a discrete state variable representing the number of seeds in the seed bank, density-dependent recruitment, and temporal variation in demography. Parameter es- timates for

Mark Rees

2006-01-01

384

Cell cycle activity and beta-tubulin accumulation during dormancy breaking of Acer platanoides L. seeds  

Microsoft Academic Search

Cell cycle events in embryo axes of Norway maple (Acer platanoides L.) seeds were studied during dormancy breaking by flow cytometric analyses of the nuclear DNA content and by immunodetection of ?-tubulin. Most embryonic nuclei of dry, fully matured seeds were arrested in the G2 phase of the cell cycle. In addition, the lowest content of ?-tubulin was detected in

T. A. Pawlowski; J. H. W. Bergervoet; R. J. Bino; S. P. C. Groot

2004-01-01

385

Polyamines in dormancy breaking of tree seeds Z. Szczotka U. Lewandowska  

E-print Network

in the physiology of dormancy breaking of Acer platanoides and Fraxi- nus excelsior seeds (in the initial stage) has in Szczotka (1984a, b). A. platanoides seeds were soaked before stratification in the following solutions. Results We observed that changes in the level of polyamine in A. platanoides seeds were similar

Paris-Sud XI, Université de

386

Potato tuber cytokinin oxidase/dehydrogenase genes: Biochemical properties, activity, and expression during tuber dormancy progression  

Technology Transfer Automated Retrieval System (TEKTRAN)

The enzymatic and biochemical properties of the proteins encoded by five potato cytokinin oxidase/dehydrogenase (CKX)-like genes functionally expressed in yeast and the effects of tuber dormancy progression on StCKX expression and cytokinin metabolism were examined in meristems isolated from field-g...

387

CHANGES IN ABA BIOSYNTHETIC AND METABOLISM-RELATED GENE EXPRESSION DURING MERISTEM DORMANCY IN POTATO TUBERS.  

Technology Transfer Automated Retrieval System (TEKTRAN)

At harvest and for an indeterminate period thereafter, potato tubers will not sprout and are physiologically dormant. Although the underlying molecular mechanisms controlling tuber dormancy are poorly understood, it has been proposed that endogenous plant hormones are intricately involved in potato ...

388

Cyclic dormancy, temperature and water availability control germination of Carrichtera annua, an invasive  

E-print Network

. Key words: annual plant, desert plant, invasive species, seasonal dormancy, temporal variability a role in reduc- ing the effects of interspecific competition (Chesson et al. 2004). Seeds of annual to germinate at any given time, creating a long-lasting soil seed bank (Kemp 1989; Facelli et al. 2005

Chesson, Peter L.

389

Costs and benefits of fruiting to future reproduction in two dormancy-prone orchids  

Microsoft Academic Search

Summary 1 Reproduction is expected to occur at a cost to survival, growth or future reproduction. However, trade-offs in long-lived, clonal herbs have proven difficult to assess, particularly when they are prone to adult dormancy. 2 We assessed the costs of fruiting in a study of two species of lady's slipper orchid, Cypripedium candidum and C. parviflorum , growing sympatrically

RICHARD P. SHEFFERSON; ELLEN L. SIMMS

2007-01-01

390

Metastatic dormancy: a complex network between cancer stem cells and their microenvironment.  

PubMed

Metastasis represents the major threat of cancer progression and generally emerges years after the detection of the primary tumor. An important rate-limiting step resides in cellular dormancy, where a disseminated tumor cell remains in a quiescent state at a remote organ. Herein we review the molecular mechanisms leading to tumor dormancy, mainly in regards to cellular quiescence and the tumor microenvironment. Based on the current published literature, we provide evidence that links the cancer stem cell (CSC) theory with dormancy and metastasis. Once a disseminated tumor cell reaches a target tissue, a tight regulation imposed by the foreign microenvironment will dictate the fate of these cells, which implies a balance in the secretion of soluble factors, modulation of the extracellular matrix and the angiogenic switch. We investigate thoroughly whether the CSC theory could also apply to metastasis initiation. In fact, the resistance of CSCs to therapy, leading to the minimal residual disease and cellular quiescence phenotypes, predisposes for the development of metastases. Finally, we describe the new technologies available for the identification of circulating tumor cells (CTCs), as well as their clinical relevance in dormancy of metastatic cancer patients. PMID:24887025

Bleau, Anne-Marie; Agliano, Alice; Larzabal, Leyre; de Aberasturi, Arrate Lopez; Calvo, Alfonso

2014-12-01

391

Temperature requirements for dormancy break and seed germination vary greatly among 14 wetland Carex species  

Microsoft Academic Search

We evaluated dormancy loss in seeds of 14 Carex species (C. atherodes, C. brevior, C. comosa, C. cristatella, C. cryptolepis, C. granularis, C. hystericina, C. lacustris, C. pellita, C. scoparia, C. stipata, C. stricta, C. utriculata, C. vulpinoidea) under growing season and stratification conditions and determined the temperature requirements for germination. Seeds were germinated for 1 year at a diel

Karin M. Kettenring; Susan M. Galatowitsch

2007-01-01

392

Temperature effects on dormancy levels and germination in temperate forest sedges (Carex)  

Microsoft Academic Search

The effects of stratification temperatures and burial in soil on dormancy levels of Carex pendula L. and C. remota L., two spring-germinating perennials occurring in moist forests, were investigated. Seeds buried for 34 months outdoors, and seeds stratified in the laboratory at temperatures between 3 and 18 °C for periods between 2 and 28 weeks, were tested over a range of

Markus Brändel; Wolfgang Schütz

2005-01-01

393

A Eukaryotic-like Ser/Thr Kinase Signals Bacteria to Exit Dormancy  

E-print Network

A Eukaryotic-like Ser/Thr Kinase Signals Bacteria to Exit Dormancy in Response to Peptidoglycan.dworkin@columbia.edu DOI 10.1016/j.cell.2008.08.039 SUMMARY Bacteria can respond to adverse environmental conditions in the local environment. Growing bacteria release muropeptide fragments of the cell wall

Symington, Lorraine S.

394

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

Microsoft Academic Search

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 the testa in the model plant Arabidopsis, we compared mutants affected in testa pigmentation and\\/or structure for

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

2000-01-01

395

Seed production temperature regulation of primary dormancy occurs through control of seed coat phenylpropanoid metabolism.  

PubMed

Environmental changes during seed production are important drivers of lot-to-lot variation in seed behaviour and enable wild species to time their life history with seasonal cues. Temperature during seed set is the dominant environmental signal determining the depth of primary dormancy, although the mechanisms though which temperature changes impart changes in dormancy state are still only partly understood. We used molecular, genetic and biochemical techniques to examine the mechanism through which temperature variation affects Arabidopsis thaliana seed dormancy. Here we show that, in Arabidopsis, low temperatures during seed maturation result in an increase in phenylpropanoid gene expression in seeds and that this correlates with higher concentrations of seed coat procyanidins. Lower maturation temperatures cause differences in coat permeability to tetrazolium, and mutants with increased seed coat permeability and/or low procyanidin concentrations are less able to enter strongly dormant states after exposure to low temperatures during seed maturation. Our data show that maternal temperature signalling regulates seed coat properties, and this is an important pathway through which the environmental signals control primary dormancy depth. PMID:25412428

MacGregor, Dana R; Kendall, Sarah L; Florance, Hannah; Fedi, Fabio; Moore, Karen; Paszkiewicz, Konrad; Smirnoff, Nicholas; Penfield, Steven

2015-01-01

396

Influence of the Testa on Seed Dormancy, Germination, and Longevity in Arabidopsis1  

Microsoft Academic Search

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 lim- iting the detrimental activity of physical and biological agents dur- ing seed storage. To analyze the function of the testa in the model plant Arabidopsis, we compared mutants affected in testa pigmen- tation

Isabelle Debeaujon; Karen M. Leon-Kloosterziel; Maarten Koornneef

2000-01-01

397

Evidence from Polygene Mapping for a Causal Relationship between Potato Tuber Dormancy and Abscisic Acid Content.  

PubMed

In previous studies polygene mapping of a backcross population derived from haploid potato (Solanum tuberosum) and a diploid wild species (Solanum berthaultii) showed at least eight quantitative trait loci (QTLs) associated with tuber dormancy. The same population was mapped for abscisic acid (ABA) content in tubers so that any QTLs identified could be compared with those detected previously. At least three distinct loci on three chromosomes (2, 4, and 7) were associated with variation in ABA content. One of the QTLs was detected only as a main (single locus) effect, and two QTLs were found through two-locus interaction analysis (epistasis). Interaction between QTLs at markers TG234 (chromosome 2) and TG155 (chromosome 4) explained 20% of total phenotypic variance for this trait. The interaction closely resembled one previously detected for dormancy, suggesting an association between high ABA content and long tuber dormancy. Although relationships between ABA level and dormancy could be demonstrated through polygene mapping, there was no indication of a relationship between these traits when they were subjected to a conventional correlation test. This illustrates the usefulness of polygene mapping as a tool to identify possible associations between hormone levels and plant development. PMID:12223876

Simko, I.; McMurry, S.; Yang, H. M.; Manschot, A.; Davies, P. J.; Ewing, E. E.

1997-12-01

398

Effect of Dormancy Breaking Treatments and Salinity on Seed Germination of Two Desert Shrubs  

Microsoft Academic Search

Hammada (Hammada salicornica Bge) and calligonum (Calligonum intertextum Rech) are dominant shrubs of sandy desert areas of Khuzestan province, in the southwest of Iran, and they are used for sand dune establishment. Seeds of these two species were collected from the wild and subjected to different dormancy breaking treatments (scarification, sulfuric acid, potassium nitrate solution, rinsing and soaking, and controlled

M. J. Bahrani; H. Niknejad-Kazempour

2007-01-01

399

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

Microsoft Academic Search

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 and germination of Chenopodium album L., Polygonum persicaria L., P. lapathifolium L. subsp. lapathifolium, Sisymbrium officinale (L.) Scop.

H. J. Bouwmeester

1990-01-01

400

Electron Tomography Reveals the Steps in Filovirus Budding  

PubMed Central

The filoviruses, Marburg and Ebola, are non-segmented negative-strand RNA viruses causing severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. The sequence of events that leads to release of filovirus particles from cells is poorly understood. Two contrasting mechanisms have been proposed, one proceeding via a “submarine-like” budding with the helical nucleocapsid emerging parallel to the plasma membrane, and the other via perpendicular “rocket-like” protrusion. Here we have infected cells with Marburg virus under BSL-4 containment conditions, and reconstructed the sequence of steps in the budding process in three dimensions using electron tomography of plastic-embedded cells. We find that highly infectious filamentous particles are released at early stages in infection. Budding proceeds via lateral association of intracellular nucleocapsid along its whole length with the plasma membrane, followed by rapid envelopment initiated at one end of the nucleocapsid, leading to a protruding intermediate. Scission results in local membrane instability at the rear of the virus. After prolonged infection, increased vesiculation of the plasma membrane correlates with changes in shape and infectivity of released viruses. Our observations demonstrate a cellular determinant of virus shape. They reconcile the contrasting models of filovirus budding and allow us to describe the sequence of events taking place during budding and release of Marburg virus. We propose that this represents a general sequence of events also followed by other filamentous and rod-shaped viruses. PMID:20442788

Welsch, Sonja; Kolesnikova, Larissa; Krähling, Verena; Riches, James D.; Becker, Stephan; Briggs, John A. G.

2010-01-01

401

Are there efferent synapses in fish taste buds?  

PubMed

In fish, nerve fibers of taste buds are organized within the bud's nerve fiber plexus. It is located between the sensory epithelium consisting of light and dark elongated cells and the basal cells. It comprises the basal parts and processes of light and dark cells that intermingle with nerve fibers, which are the dendritic endings of the taste sensory neurons belonging to the cranial nerves VII, IX or X. Most of the synapses at the plexus are afferent; they have synaptic vesicles on the light (or dark) cells side, which is presynaptic. In contrast, the presumed efferent synapses may be rich in synaptic vesicles on the nerve fibers (presynaptic) side, whereas the cells (postsynaptic) side may contain a subsynaptic cistern; a flat compartment of the smooth endoplasmic reticulum. This structure is regarded as a prerequisite of a typical efferent synapse, as occurring in cochlear and vestibular hair cells. In fish taste buds, efferent synapses are rare and were found only in a few species that belong to different taxa. The significance of efferent synapses in fish taste buds is not well understood, because efferent connections between the gustatory nuclei of the medulla with taste buds are not yet proved. PMID:16217620

Reutter, Klaus; Witt, Martin

2004-12-01

402

Electron tomography reveals the steps in filovirus budding.  

PubMed

The filoviruses, Marburg and Ebola, are non-segmented negative-strand RNA viruses causing severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. The sequence of events that leads to release of filovirus particles from cells is poorly understood. Two contrasting mechanisms have been proposed, one proceeding via a "submarine-like" budding with the helical nucleocapsid emerging parallel to the plasma membrane, and the other via perpendicular "rocket-like" protrusion. Here we have infected cells with Marburg virus under BSL-4 containment conditions, and reconstructed the sequence of steps in the budding process in three dimensions using electron tomography of plastic-embedded cells. We find that highly infectious filamentous particles are released at early stages in infection. Budding proceeds via lateral association of intracellular nucleocapsid along its whole length with the plasma membrane, followed by rapid envelopment initiated at one end of the nucleocapsid, leading to a protruding intermediate. Scission results in local membrane instability at the rear of the virus. After prolonged infection, increased vesiculation of the plasma membrane correlates with changes in shape and infectivity of released viruses. Our observations demonstrate a cellular determinant of virus shape. They reconcile the contrasting models of filovirus budding and allow us to describe the sequence of events taking place during budding and release of Marburg virus. We propose that this represents a general sequence of events also followed by other filamentous and rod-shaped viruses. PMID:20442788

Welsch, Sonja; Kolesnikova, Larissa; Krähling, Verena; Riches, James D; Becker, Stephan; Briggs, John A G

2010-04-01

403

Stromal Protein Ecm1 Regulates Ureteric Bud Patterning and Branching  

PubMed Central

The interactions between the nephrogenic mesenchyme and the ureteric bud during kidney development are well documented. While recent studies have shed some light on the importance of the stroma during renal development, many of the signals generated in the stroma, the genetic pathways and interaction networks involving the stroma are yet to be identified. Our previous studies demonstrate that retinoids are crucial for branching of the ureteric bud and for patterning of the cortical stroma. In the present study we demonstrate that autocrine retinoic acid (RA) signaling in stromal cells is critical for their survival and patterning, and show that Extracellular matrix 1, Ecm1, a gene that in humans causes irritable bowel syndrome and lipoid proteinosis, is a novel RA-regulated target in the developing kidney, which is secreted from the cortical stromal cells surrounding the cap mesenchyme and ureteric bud. Our studies suggest that Ecm1 is required in the ureteric bud for regulating the distribution of Ret which is normally restricted to the tips, as inhibition of Ecm1 results in an expanded domain of Ret expression and reduced numbers of branches. We propose a model in which retinoid signaling in the stroma activates expression of Ecm1, which in turn down-regulates Ret expression in the ureteric bud cleft, where bifurcation normally occurs and normal branching progresses. PMID:24391906

Paroly, Suneeta S.; Wang, Fengwei; Spraggon, Lee; Merregaert, Joseph; Batourina, Ekatherina; Tycko, Benjamin; Schmidt-Ott, Kai M.; Grimmond, Sean; Little, Melissa; Mendelsohn, Cathy

2013-01-01

404

Repellence of the red bud borer Resseliella oculiperda from grafted apple trees by impregnation of rubber budding strips with essential oils.  

PubMed

The red bud borer Resseliella oculiperda (Rübs.) is a pest insect of apple trees when rootstocks are grafted with scion buds by 'shield budding'. The female midges are attracted to the wounds of the grafted buds where they lay their eggs. The larvae feed on the cambium and destroy the buds completely or partially, leading to bad union of the buds with the rootstocks. Budding strips are used very often by growers to bind scion buds to rootstocks. These strips cannot prevent midges from reaching the damaged tissue. Chemical treatments applied to the grafts and other types of strip do not provide better protection against the pest and may cause other risks for growers. In orchard experiments in 2000 and 2001, the authors evaluated the repellent action provided by three essential oils and five compounds of plant origin against the midges by impregnating budding strips with them. The essential oils of lavender, Lavandula angustifolia (P. Mill.), and alpha-terpineol decreased the infestation of buds by more than 95 and 80% respectively. The other potential repellents tested [the essential oil of Juniperus virginiana (L.), citronellal, the essential oil of Cinnamomum camphora (L.) J. Presl, R-carvone, linalool and R-fenchone] decreased infestation by 67, 66, 51, 45, 37 and 25% respectively. The formulation and commercial development of budding strips impregnated with lavender oil is discussed. PMID:17421054

van Tol, Rob W H M; Swarts, Henk J; van der Linden, Anton; Visser, J H

2007-05-01

405

Proteomic changes during tuber dormancy release process revealed by iTRAQ quantitative proteomics in potato.  

PubMed

Given that limited information is available with regard to tuber dormancy release related proteome, we conducted proteome analysis of tuber dormancy release process at dormant tuber (DT), dormancy release tuber (DRT) and sprouting tuber (ST) using the iTRAQ technology. A total of 1,752 proteins were identified. Among them, a subset of 316 proteins was screened as significant up- (137) and down regulated (179) between DT vs DRT. A subset of 120 proteins experienced significant up- (40) or down-regulation (80) between DRT vs ST. The differentially expressed proteins were grouped into 11 functional categories. Proteins enriched in functional categories of major carbohydrate (CHO) metabolism, glycolysis, fermentation, amino acid metabolism, protein and transport were highly up-regulated, while functional categories of photosynthesis and RNA were down-regulated between DT vs DRT. Proteins enriched in functional groups of protein, cell wall, lipid metabolism, miscellaneous, and signaling were strongly up-regulated, while functional categories of photosynthesis, hormone metabolism and protein were down-regulated between DRT vs ST. Consistent with previous documented differentially expressed genes, most of differentially expressed proteins were also identified between DT and DRT, indicating the metabolism shift from growth suspension to growth activation as tubers dormancy breaking. The changes in protein profiles showed lower concordance with corresponding alterations in transcript levels, indicating possible transcriptional and posttranscriptional regulation. Furthermore, the possible mechanism of tuber dormancy release was discussed in relation to what was known in transcripts change and other plant models from carbohydrate metabolism, protein metabolism, stress response, redox regulation, transcription regulation, DNA metabolism, amino acid metabolism, development, signaling as well as hormone metabolism. PMID:25514565

Liu, Bailin; Zhang, Ning; Zhao, Shuo; Chang, Jing; Wang, Zemin; Zhang, Guodong; Si, Huaijun; Wang, Di

2015-01-01

406

Physiological epicotyl dormancy and recalcitrant storage behaviour in seeds of two tropical Fabaceae (subfamily Caesalpinioideae) species  

PubMed Central

Background and aims Physiological epicotyl dormancy in which the epicotyl elongates inside the seed before the shoot emerges has been reported for only a few tropical rainforest species, all of which are trees that produce recalcitrant seeds. In studies on seeds of Fabaceae in Sri Lanka, we observed a considerable time delay in shoot emergence following root emergence in seeds of the introduced caesalpinioid legumes Brownea coccinea and Cynometra cauliflora. Thus, our aim was to determine if seeds of these two tropical rainforest trees have physiological epicotyl dormancy, and also if they are recalcitrant, i.e. desiccation sensitive. Methodology Fresh seeds were (i) dried to various moisture levels, and (ii) stored at ?1 and 5 °C to determine loss (or not) of viability and thus type of seed storage behaviour (orthodox, recalcitrant or intermediate). To identify the kind of dormancy, we tested the effect of scarification on imbibition and monitored radicle emergence and epicotyl growth (inside the seed) and emergence. Principal results Fresh seeds of both species had high moisture content (MC): 50 % for C. cauliflora and 30 % for B. coccinea. Further, all seeds of C. cauliflora and the majority of those of B. coccinea lost viability when dried to 15 % MC; most seeds of both species also lost viability during storage at ?1 or 5 °C. Intact seeds of both species were water permeable, and radicles emerged in a high percentage of them in <30 days. However, shoot emergence lagged behind root emergence by 77 ± 14 days in B. coccinea and by 38 ± 4 days in C. cauliflora. Further, plumule growth inside seeds of C. cauliflora began almost immediately after radicle emergence but not until ?30–35 days in B. coccinea seeds. Conclusions Seeds of both species are recalcitrant and have physiological epicotyl dormancy. The kind of physiological epicotyl dormancy in seeds of C. cauliflora has not been described previously; the formula is Cnd (root)? (epicotyl). PMID:23264873

Jayasuriya, K. M. G. Gehan; Wijetunga, Asanga S. T. B.; Baskin, Jerry M.; Baskin, Carol C.

2012-01-01

407

The first day of clinical trials for Gleevec, Bud and YvonneSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

Interviewee: Bud DNAi Location:Applications>Genes and medicine>drug design>Bud's Story>The first patient The first patient Yvonne, Bud's wife, talks about the first day of the clinical trials in June of 1998

2008-03-26

408

Electrostatic Levitation of Plant Seeds and Flower Buds  

NASA Astrophysics Data System (ADS)

We report the electrostatic levitation of various kinds of seeds and flower buds. Coral berry and pepper near a spherical shape show a stable levitation state. The prolate ellipsoid soybean and flower buds are always “standing" in the free space with satisfactory levitation stability. For the irregular mushroom and wheat grain, the levitation state is characterized as a “top-heavy" posture. These special stable equilibrium states are proved by the analysis of surface charge distribution. The obtained saturation polarization charge of samples presents a good accordance with experimental data. The levitation ability is weighed by the factor m(inr+2)/(inrD2).

Hu, Liang; Wang, Hai-Peng; Li, Liu-Hui; Wei, Bing-Bo

2012-06-01

409

Project BudBurst: People, Plants, and Climate Change  

NASA Astrophysics Data System (ADS)

Providing opportunities for individuals to contribute to a better understanding of climate change is the hallmark of Project BudBurst (www.budburst.org). This highly successful, national citizen science program, now in its third year, is bringing climate change education outreach to thousands of individuals. Project BudBurst is a national citizen science initiative designed to engage the public in observations of phenological (plant life cycle) events that raise awareness of climate change, and create a cadre of informed citizen scientists. Citizen science programs such as Project BudBurst provide the opportunity for students and interested laypersons to actively participate in scientific research. Such programs are important not only from an educational perspective, but because they also enable scientists to broaden the geographic and temporal scale of their observations. The goals of Project BudBurst are to 1) increase awareness of phenology as an area of scientific study; 2) Increase awareness of the impacts of changing climates on plants; and 3) increase science literacy by engaging participants in the scientific process. From its 2008 launch in February, this on-line educational and data-entry program, engaged participants of all ages and walks of life in recording the timing of the leafing and flowering of wild and cultivated species found across the continent. Thus far, thousands of participants from all 50 states have submitted data. Project BudBurst has been the subject of almost 200 media outlets including NPR, national and regional television broadcasts, and most of the major national and regional newspapers. This presentation will provide an overview of Project BudBurst and will report on the results of the 2009 field campaign and discuss plans to expand Project BudBurst in 2010 including the use of mobile phones applications for data collection and reporting from the field. Project BudBurst co managed by the National Ecological Observatory Network and the Chicago botanic Garden. Financial support has been received from the National Science Foundation, UCLA Center for Embedded network Sensors U.S. Bureau of Land Management, U.S. Geological Survey , National Geographic Education Foundation, U.S. Fish and Wildlife Foundation, and NASA.

Henderson, S.; Ward, D.; Havens, K.; Gardiner, L. S.; Alaback, P.

2010-12-01

410

Changes in histone H3 and H4 multi-acetylation during natural and forced dormancy break in potato tubers.  

PubMed

The effects of post-harvest storage and dormancy progression on histone acetylation patterns were examined in potato (Solanum tuberosum L. cv. Russet Burbank) tubers. Storage of field-grown tubers at 3 degrees C in the dark resulted in the progressive loss of tuber meristem dormancy, defined as measurable growth after transfer to 20 degrees C for 7 days. Dormancy emergence was concomitant with sustained increases in histone H3.1 and H3.2 multi-acetylation, and with transient increases in H4 multi-acetylation that peaked 4-5 months post-harvest. Treatment of dormant tubers with bromoethane (BE) resulted in rapid loss of dormancy over 9 days. Similar to cold-stored field-grown tubers, dormancy break in BE-treated tubers occurred at the same time as transient rises in H4 and H3.1/3.2 multi-acetylation, peaking at days 1 and 4, respectively. BE treatment also resulted in small increases in RNA synthesis at day 6, and a three-fold, sustained activation of DNA synthesis thereafter. A defined sequence of epigenetic events, beginning with previously characterized transient cytosine demethylation, followed by increased H3 and H4 histone acetylation and ultimately, tuber meristem re-activation, may thus exist in potatoes during dormancy exit and resumption of rapid growth. PMID:15032826

David Law, R.; Suttle, Jeffrey C.

2004-04-01

411

A novel role for histone methyltransferase KYP/SUVH4 in the control of Arabidopsis primary seed dormancy.  

PubMed

• Seed dormancy controls germination and plays a crucial role in the life cycle of plants. Chromatin modifications are involved in the regulation of seed dormancy; however, little is known about the underlying mechanism. • KYP/SUVH4 is required for histone H3 lysine 9 dimethylation. Mutations in this gene cause increased seed dormancy. KYP/SUVH4-overexpressing Arabidopsis plants show decreased dormancy. KYP/SUVH4 expression is regulated by abscisic acid (ABA) and gibberellins (GA). The sensitivity of seed germination to ABA and paclobutrazol (PAC) is enhanced slightly in kryptonite-2 (kyp-2) and suvh4-2/suvh5 mutants, but weakened in KYP/SUVH4-overexpressing plants. • In the kyp-2 mutant, several dormancy-related genes, including DOG1 and ABI3, show increased expression levels, in agreement with a negative role for KYP/SUVH4 in gene transcription. • Genetic analysis showed that DOG1 and HUB1 are epistatic to KYP/SUVH4, suggesting that these genes regulate seed dormancy in the same genetic pathway. PMID:22122546

Zheng, Jian; Chen, Fengying; Wang, Zhi; Cao, Hong; Li, Xiaoying; Deng, Xin; Soppe, Wim J J; Li, Yong; Liu, Yongxiu

2012-02-01

412

Spermidine and flower-bud differentiation in thin-layer explants of tobacco  

Microsoft Academic Search

Three lines of evidence indicate a connection between high spermidine levels and floral initiation in thin-layer tissue cultures of Wisconsin-38 tobacco (Nicotiana tabacum L.). (1) Spermidine levels are much higher in floral buds than in vegetative buds. (2) Inhibition of spermidine synthesis by cyclohexylamine prevents the rise in spermidine titer, inhibits floral initiation and promotes the formation of vegetative buds

R. Kaur-Sawhney; A. F. Tiburcio; A. W. Galston

1988-01-01

413

Molecular events of apical bud formation in white spruce, Picea glauca.  

PubMed

Bud formation is an adaptive trait that temperate forest trees have acquired to facilitate seasonal synchronization. We have characterized transcriptome-level changes that occur during bud formation of white spruce [Picea glauca (Moench) Voss], a primarily determinate species in which preformed stem units contained within the apical bud constitute most of next season's growth. Microarray analysis identified 4460 differentially expressed sequences in shoot tips during short day-induced bud formation. Cluster analysis revealed distinct temporal patterns of expression, and functional classification of genes in these clusters implied molecular processes that coincide with anatomical changes occurring in the developing bud. Comparing expression profiles in developing buds under long day and short day conditions identified possible photoperiod-responsive genes that may not be essential for bud development. Several genes putatively associated with hormone signalling were identified, and hormone quantification revealed distinct profiles for abscisic acid (ABA), cytokinins, auxin and their metabolites that can be related to morphological changes to the bud. Comparison of gene expression profiles during bud formation in different tissues revealed 108 genes that are differentially expressed only in developing buds and show greater transcript abundance in developing buds than other tissues. These findings provide a temporal roadmap of bud formation in white spruce. PMID:21118421

El Kayal, Walid; Allen, Carmen C G; Ju, Chelsea J-T; Adams, Eri; King-Jones, Susanne; Zaharia, L Irina; Abrams, Suzanne R; Cooke, Janice E K

2011-03-01

414

Shoot preformation in clones of Fraxinus pennsylvanica in relation to site and year of bud formation  

Microsoft Academic Search

Shoot preformation was investigated in buds of four clones of Fraxinus pennsylvanica var. subintegerrima (Vahl) Fern. at two sites in Manitoba in the second (1988) and third (1989) growing seasons after grafting. More preformed primordia were produced in terminal buds in 1989 compared to 1988 at each site. Both terminal and lateral buds at Morden contained significantly more primordia than

W. R. Remphrey; C. G. Davidson

1994-01-01

415

Chromosome condensation and sister chromatid pairing in budding yeast  

Microsoft Academic Search

We have developed a fluorescent in situ hy- bridization (FISH) method to examine the structure of both natural chromosomes and small artificial chromo- somes during the mitotic cycle of budding yeast. Our results suggest that the pairing of sister chromatids: (a) occurs near the centromere and at multiple places along the chromosome arm as has been observed in other eukaryotic

Vincent Guacci; Eileen Hogan; Douglas Koshland

1994-01-01

416

Mechanisms of Budding of Nanoscale Particles through Lipid Bilayers  

PubMed Central

We examine the budding of a nanoscale particle through a lipid bilayer using molecular dynamics simulations, free energy calculations, and an elastic theory, with the aim of determining the extent to which equilibrium elasticity theory can describe the factors that control the mechanism and efficiency of budding. The particle is a smooth sphere which experiences attractive interactions to the lipid head groups. Depending on the parameters, we observe four classes of dynamical trajectories: particle adhesion to the membrane, stalled partially wrapped states, budding followed by scission, and membrane rupture. In most regions of parameter space we find that the elastic theory agrees nearly quantitatively with the simulated phase behavior as a function of adhesion strength, membrane bending rigidity, and particle radius. However, at parameter values near the transition between particle adhesion and budding, we observe long-lived partially wrapped states which are not captured by existing elastic theories. These states could constrain the accessible system parameters for those enveloped viruses or drug delivery vehicles which rely on exo- or endocytosis for membrane transport. PMID:22803595

Ruiz-Herrero, Teresa; Velasco, Enrique; Hagan, Michael F.

2012-01-01

417

Nipped in the Bud: Suppression of the China Democracy Party  

NSDL National Science Digital Library

In September, Human Rights Watch posted five new reports on their Website. Nipped in the Bud: Suppression of the China Democracy Party examines the situation of more than 30 people imprisoned for their role in the China Democracy Party and argues for their immediate release.

418

Early Replication of Short Telomeres in Budding Yeast  

E-print Network

Early Replication of Short Telomeres in Budding Yeast Alessandro Bianchi1, * and David Shore1 1.bianchi@molbio.unige.ch DOI 10.1016/j.cell.2007.01.041 SUMMARY The maintenance of an appropriate number of telomere repeats by telomerase is essential for proper chromosome protection. The action of telomerase at the telomere terminus

Halazonetis, Thanos

419

Soluble Sugar Concentrations Associated with Tuber and Winter Bud Sprouting  

Microsoft Academic Search

Many aquatic weeds rely on vegetative structures for surviv- al and propagation, rather than seeds. American pondweed ( Potamogeton nodosus Poiret) winter buds , and hydrilla ( Hydril- la verticillata (L.f.) Royle, monoecious and dioecious types) tubers were allowed to sprout in water in the dark. At two-to- three day intervals individual propagules and dependent shoots were analyzed for soluble

D. F. SPENCER; F. J. RYAN; L. AUNG; G. G. KSANDER

2001-01-01

420

Stem diameter changes before bud opening in Zelkova serrata saplings.  

PubMed

It is well known that stems of woody plants shrink and swell diurnally. These fluctuations of stem diameter are induced mainly by the changes of water contents in plants, which are caused by the combination of leaf transpiration and root absorption of water. This implies that dormant-like deciduous broadleaved trees in a leafless state should show no or less changes in stem diameter. However, some physiological activities in woody plants are also known to precede their winter bud opening. Whether and how diameter changes occur in deciduous tree stems during winter was investigated using Zelkova serrata saplings in a leafless state. Measurements of stem diameter changes were done for more than 4 months continuously. The saplings showed distinct diameter changes with periodicities from diurnal to a few weeks, and these changes were initiated 2 months before winter bud opening. These results indicate that some physiological and/or developmental activities occur in the stem of deciduous trees before winter bud opening, and do not correspond to changes in water relations as a result of leaf transpiration. These internal activities cause fluctuations in stem diameter prior to winter bud opening in deciduous trees. PMID:12605295

Yoda, Kiyotsugu; Wagatsuma, Hiromichi; Suzuki, Mitsuo; Suzuki, Hitoshi

2003-02-01

421

Identification of cis-elements that regulate gene expression during initiation of axillary bud outgrowth in Arabidopsis.  

PubMed

Growth regulation associated with dormancy is an essential element in plant life cycles. To reveal regulatory mechanisms of bud outgrowth, we analyzed transcriptomes of axillary shoots before and after main stem decapitation in Arabidopsis (Arabidopsis thaliana). We searched for any enriched motifs among the upstream regions of up-regulated and down-regulated genes after decapitation. The promoters of down-regulated genes were enriched for TTATCC motifs that resemble the sugar-repressive element, whereas the promoters of up-regulated genes were enriched for GGCCCAWW and AAACCCTA, designated Up1 and Up2, respectively. Transgenic plants harboring a reporter gene driven by a tandem repeat of the elements were produced to analyze their function in vivo. Sugar-repressive element-mediated gene expression was down-regulated by the application of sugars but was unaffected after decapitation. In contrast, expression driven by the repeat containing both Up1 and Up2 was up-regulated after decapitation, although the Up1 or Up2 repeat alone failed to induce reporter gene expression in axillary shoots. In addition, disruption of both Up1 and Up2 elements in a ribosomal protein gene abolished the decapitation-induced expression. Ontological analysis demonstrated that up-regulated genes with Up elements were disproportionately predicted to function in protein synthesis and cell cycle. Up1 is similar to an element known to be a potential target for TCP (TEOSINTE BRANCHED1, CYCLOIDEA, PCFs family) transcription factor(s), which regulate expression of cell cycle-related and ribosomal protein genes. Our data indicate that Up1-mediated transcription of protein synthesis and cell cycle genes is an important regulatory step during the initiation of axillary shoot outgrowth induced by decapitation. PMID:15908603

Tatematsu, Kiyoshi; Ward, Sally; Leyser, Ottoline; Kamiya, Yuji; Nambara, Eiji

2005-06-01

422

Project BudBurst: Citizen Science for All Seasons  

NASA Astrophysics Data System (ADS)

Providing opportunities for individuals to contribute to a better understanding of climate change is the hallmark of Project BudBurst (www.budburst.org). This highly successful, national citizen science program, now in its second year, is bringing climate change education outreach to thousands of individuals. Project BudBurst is a national citizen science initiative designed to engage the public in observations of phenological (plant life cycle) events that raise awareness of climate change, and create a cadre of informed citizen scientists. Citizen science programs such as Project BudBurst provide the opportunity for students and interested laypersons to actively participate in scientific research. Such programs are important not only from an educational perspective, but because they also enable scientists to broaden the geographic and temporal scale of their observations. The goals of Project BudBurst are to 1) increase awareness of phenology as an area of scientific study; 2) Increase awareness of the impacts of changing climates on plants; and 3) increase science literacy by engaging participants in the scientific process. From its 2008 launch in February, this on-line educational and data-entry program, engaged participants of all ages and walks of life in recording the timing of the leafing and flowering of wild and cultivated species found across the continent. Thus far, participants from 49 states have submitted data that is being submitted to the USA National Phenology Network (www.usanpn.org) database. Project BudBurst has been the subject of almost 200 media outlets including NPR, national and regional television broadcasts, and most of the major national and regional newspapers. This presentation will provide an overview of Project Budburst and will report on the results of the 2008 field campaign and discuss plans to expand Project BudBurst in 2009. Project BudBurst is a Windows to the Universe Citizen Science program managed by the University Corporation for Atmospheric Research, the Chicago Botanic Garden, University of Montana in collaboration with the USA -National Phenology Network and with financial support from U.S. Bureau of Land Management, U.S. Geological Survey, NEON, and the Fish and Wildlife Foundation.

Meymaris, K.; Henderson, S.; Alaback, P.; Havens, K.

2008-12-01

423

Deoxyuridine triphosphatase expression defines the transition from dormant to sprouting potato tuber buds  

Microsoft Academic Search

Identification of molecular markers defining the end of tuber dormancy prior to visible sprouting is of agronomic interest\\u000a for potato growers and the potato processing industry. In potato tubers, breakage of dormancy is associated with the reactivation\\u000a of meristem function. In dormant meristems, cells are arrested in the G1\\/G0 phase of the cell cycle and re-entry into the G1 phase

Melanie SenningUwe Sonnewald; Uwe Sonnewald; Sophia Sonnewald

2010-01-01

424

Selection for low or high primary dormancy in Lolium rigidum Gaud seeds results in constitutive differences in stress protein expression and peroxidase activity  

PubMed Central

Seed dormancy in wild Lolium rigidum Gaud (annual ryegrass) populations is highly variable and not well characterized at the biochemical level. To identify some of the determinants of dormancy level in these seeds, the proteomes of subpopulations selected for low and high levels of primary dormancy were compared by two-dimensional polyacrylamide gel electrophoresis of extracts from mature, dry seeds. High-dormancy seeds showed higher expression of small heat shock proteins, enolase, and glyoxalase I than the low-dormancy seeds. The functional relevance of these differences in protein expression was confirmed by the fact that high-dormancy seeds were more tolerant to high temperatures imposed at imbibition and had consistently higher glyoxalase I activity over 0–42?d dark stratification. Higher expression of a putative glutathione peroxidase in low-dormancy seeds was not accompanied by higher activity, but these seeds had a slightly more oxidized glutathione pool and higher total peroxidase activity. Overall, these biochemical and physiological differences suggest that L. rigidum seeds selected for low dormancy are more prepared for rapid germination via peroxidase-mediated cell wall weakening, whilst seeds selected for high dormancy are constitutively prepared to survive environmental stresses, even in the absence of stress during seed development. PMID:20974739

Goggin, Danica E.; Powles, Stephen B.; Steadman, Kathryn J.

2011-01-01

425

Regulation of cell cycle regulators by environmental signals during growth-dormancy cycle of trees  

PubMed Central

Climate change such as changing temperature and increasing concentrations of atmospheric CO2, are likely to drive significant modifications in forests. While many studies have demonstrated the responses and adoptions of tree to fluctuations in climatic and environmental conditions, the impact of environmental signals on trees is complex and poorly understood with respect to the molecular biology in context of the seasonal change of environmental signals. This addendum is focused on the impact of environmental signals on growth-dormancy cycle of trees growing in temperate regions, especially the regulation of cell cycle regulators by temperature and photoperiod. In addition, the plant hormone control of growth-dormancy cycle of trees and cell cycle regulators in the cambium is also discussed. PMID:19826221

Li, Wan-Feng; Cui, Ke-Ming

2009-01-01

426

Abscisic acid and the regulation of embryo dormancy in the genus Acer.  

PubMed

Germination of Acer pseudoplatanus L. and Acer platanoides L. seeds was increased by moist storage of the intact fruits (seed + pericarp) at 5 degrees C, but not at 17 degrees C. In both species, germinative capacity of isolated embryos (seeds with testa removed) was increased by moist storage of fruits at either 5 or 17 degrees C. Thus dormancy loss by intact seeds and excised embryos was not necessarily correlated. Loss of dormancy in isolated embryos was associated with a reduction in free abscisic acid (ABA) content. Embryos from freshly harvested fruits of A. pseudoplatanus had a higher germinative capacity and a lower free ABA content than embryos from freshly harvested fruits of A. platanoides. Morever, germinative capacity increased, and free ABA content decreased, more rapidly with length of fruit storage in A. platanoides embryos than in A. pseudoplatanus embryos. PMID:14972962

Pinfield, N J; Stutchbury, P A; Bazaid, S A; Gwarazimba, V E

1990-03-01

427

Gene expression during seed maturation in Brassica napus in relation to the induction of secondary dormancy.  

PubMed

Gene expression in two cultivars of Brassica napus (AC Excel and DH12075) has been compared at the full-size embryo, desiccation, and mature stages of seed development. Seed of these cultivars differ in their potential to exhibit secondary dormancy following environmental stress; Excel has high potential and DH12075 has low potential. A majority of genes were down-regulated during maturation in both cultivars but a significant number of differences in gene expression between the cultivars were apparent in the transition from full-size embryo to mature seed. However, most differences were apparent in the desiccation stage and some of the differences were in genes related to signaling processes and protein biosynthesis. We suggest that the propensity of Brassica seeds to manifest secondary dormancy may be determined by changes in gene expression that occur during late seed development. PMID:17207603

Fei, Houman; Tsang, Edward; Cutler, Adrian J

2007-03-01

428

Microbial dormancy in batch cultures as a function of substrate-dependent mortality.  

PubMed

We present models and computational studies of dormancy in batch cultures to try to understand the relationship between reculturing time and death penalty for low substrate and the relative advantage of fast versus slow reawakening on the part of the bacteria. We find that the advantage goes to the faster waker for shorter reculturing times and lower mortality under low substrate, and moves to the slower waker as reculturing times and death penalty increase. The advantage returns again to the fast waker for very high death penalties. We use an explicit, continuous structure variable to represent dormancy so as to allow for flexibility in substrate usage on the part of dormant cells, and for a more mechanistic representation of the reawakening process. PMID:22004996

Ayati, Bruce P

2012-01-21

429

Nitric oxide implication in the control of seed dormancy and germination  

PubMed Central

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-dependent protein post-translational modifications are proposed as a key mechanism underlying NO signaling during early seed germination. PMID:24065970

Arc, Erwann; Galland, Marc; Godin, Béatrice; Cueff, Gwendal; Rajjou, Loïc

2013-01-01

430

Dark CO2 Fixation in Gladiolus Cormels and Its Regulation during the Break of Dormancy 1  

PubMed Central

The increase in dark CO2 fixation during cold storage of Gladiolus x gandavensis van Houtte-type grandiflorus cormels is used to monitor changes in their state of dormancy. Dark fixation is also promoted by benzyladenine, which breaks cormel dormancy, and is inhibited by abscisic acid and gibberellin A3, which inhibit cormel germination. The rate of dark fixation by nondormant cormels is five times higher than that in dormant ones. Dark fixation is not due to microorganisms. It is temperature-dependent and can be measured stoichiometrically in vivo. The apex and base of the cormels accumulate more label than the central part. Dark fixation of both dormant and nondormant cormels is also promoted by imbibition in water. The fate of the labeled assimilates was followed by ion exchange chromatography. PMID:16659256

Ginzburg, Chen

1975-01-01

431

Dark CO(2) Fixation in Gladiolus Cormels and Its Regulation during the Break of Dormancy.  

PubMed

The increase in dark CO(2) fixation during cold storage of Gladiolus x gandavensis van Houtte-type grandiflorus cormels is used to monitor changes in their state of dormancy. Dark fixation is also promoted by benzyladenine, which breaks cormel dormancy, and is inhibited by abscisic acid and gibberellin A(3), which inhibit cormel germination. The rate of dark fixation by nondormant cormels is five times higher than that in dormant ones. Dark fixation is not due to microorganisms. It is temperature-dependent and can be measured stoichiometrically in vivo. The apex and base of the cormels accumulate more label than the central part. Dark fixation of both dormant and nondormant cormels is also promoted by imbibition in water. The fate of the labeled assimilates was followed by ion exchange chromatography. PMID:16659256

Ginzburg, C

1975-07-01

432

Influence of temperature on bud break, shoot growth, flower bud atrophy and winter production of glasshouse roses  

Microsoft Academic Search

The influence of temperature in the range 15-22 °C on growth, production, quality and flower bud atrophy ('blindness') of the rose cultivars Sweet Promise and Varlon was studied. The roses were grown in Dutch glasshouse soil under natural light conditions and studied from October until May during 7 successive years. The influence of the distribution of the air temperature between

Berg van den G. A

1987-01-01

433

Cell Cycle Activity and ?-Tubulin Accumulation During Dormancy Breaking of Acer platanoides L. seeds  

Microsoft Academic Search

Cell cycle events in embryo axes of Norway maple (Acer platanoides L.) seeds were studied during dormancy breaking by flow cytometric analyses of the nuclear DNA content and by immunodetection\\u000a of ?-tubulin. Most embryonic nuclei of dry, fully matured seeds were arrested in the G2 phase of the cell cycle. In addition, the lowest content of ?-tubulin was detected in

T. A. Paw?owski; J. H. W. Bergervoet; R. J. Bino; S. P. C. Groot

2004-01-01

434

[Variability in the dormancy of seeds of Securigera securidaca (L.) Deg. et Dorfl. Preliminary note].  

PubMed

The germination rate of seeds of Securigera securidaca varied abruptly from 0% to 100% in different years of maturation, and this variability did not seem to be due to climatic differences during the period of seed maturation. These seeds showed also polymorphism in colour, which appeared to be related with varying depths of dormancy. This last one seemed to be increased by a short ageing of the seeds. PMID:6525259

Roti-Michelozzi, G; Tirteo, P

1984-11-30

435

LIFE HISTORY TRADE-OFFS IN A RARE ORCHID: THE COSTS OF FLOWERING, DORMANCY, AND SPROUTING  

Microsoft Academic Search

We tested for life history trade-offs among dormancy, sprouting, and flow- ering in a seven-year study of a threatened, perennial plant, the small yellow lady's slipper orchid (Cypripedium calceolusssp. parviflorum (Salisb.) Fernald). The aboveground states of 629 genets were monitored over seven years in a wet meadow in northeastern Illinois, USA. With mark-recapture statistics, survival, resighting, and stage transitions were

Richard P. Shefferson; Joyce Proper; Steven R. Beissinger; Ellen L. Simms

2003-01-01

436

Dormancy of Nicotiana benthamiana seeds can be broken by different compounds  

Microsoft Academic Search

The influence of after-ripening, sodium nitroprusside, potassium ferricyanide, cyanide, paclobutrazol and nitrite on germination\\u000a of seeds of Nicotiana benthamiana was investigated as well as the influence of plant hormones such as gibberellins and abscisic acid. Dormancy of N. benthamiana seeds was broken by all treatments except treatments with abscisic acid, paclobutrazol and gibberellic acid (GA3). Gibberellins had an interesting effect

Andrea Wünschová; Veronika Be?ová; Helena Vlašínová; Ladislav Havel

2009-01-01

437

Bibliography of References Related to Seed Dormancy and/or Germination in Higher Plants  

NSDL National Science Digital Library

This online bibliography is an extensive resource with a particular focus on early seed dormancy literature. Professor G.M. Simpson from the University of Saskatchewan has compiled this bibliography of 12,000 sources dating back to the 1890's. The bibliography has a user friendly search function and help page, and a history list of each session is available until the user exits the database.

Simpson, G. M.

2008-09-15

438

Association studies of dormancy and cooking quality traits in direct-seeded indica rice.  

PubMed

Association analysis was applied to a panel of accessions of Assam rice (indica) using 98 SSR markers for dormancy-related traits and cooking quality. Analysis of population structure revealed 10 subgroups in the population. The mean r(2) and D' value for all intrachromosomal loci pairs was 0.24 and 0.51, respectively. Linkage disequilibrium between linked markers decreased with distance. Marker-trait associations were investigated using the unified mixed-model approach, considering both population structure (Q) and kinship (K). Genome-wide scanning, detected a total of seven significant marker-trait associations (P < 0.01), with the R(2) values ranging from 12.0 to 18.0%. The significant marker associations were for grain dormancy (RM27 on chromosome 2), ?-amylase activity (RM27 and RM234 on chromosomes 2 and 7, respectively), germination (RM27 and RM106 on chromosome 2), amylose (RM282 on chromosome 3) and grain length elongation ratio (RM142 on chromosome 4). The present study revealed the association of marker RM27 with traits like dormancy, ?-amylase activity and germination. Simple correlation analysis of these traits revealed that these traits were positively correlated with each other and this marker may be useful for simultaneous improvement of these traits. The study indicates the presence of novel QTLs for a few traits under consideration. The study reveals association of traits like dormancy, ?-amylase activity, germination, amylose content, grain length elongation ratio with SSR markers indicating the feasibility of undertaking association analysis in conjunction with germplasm characterization. PMID:24840818

Rathi, Sunayana; Pathak, K; Yadav, R N S; Kumar, B; Sarma, R N

2014-04-01

439

Tools for Carex revegetation in freshwater wetlands: understanding dormancy loss and germination temperature requirements  

Microsoft Academic Search

Carex is a globally distributed genus with more than 2000 species worldwide and Carex species are the characteristic vegetation of sedge meadow wetlands. In the mid-continental United States, Carex species are dominant in natural freshwater wetlands yet are slow to recolonize hydrologically restored wetlands. To aid in\\u000a Carex revegetation efforts, we determined the dormancy breaking and temperature germination requirements of

Karin M. Kettenring; Susan M. Galatowitsch

2007-01-01

440

Rate of Change in Dormancy Level and Light Requirement in Weed Seeds During Stratification  

Microsoft Academic Search

The rate of change in dormancy level and light requirement, induced during stratification at 3.2 °C, was investigated in seeds ofStellaria media, Cerastium fontanum, Veronica agrestisandTaraxacum officinale.Two stratification environments, soil and wet filter paper in petri-dishes, were used. On nine occasions during a 6 week stratification period, germination was tested under three light conditions at 3.5\\/18.5 °C: (1) darkness; (2)

ANGELA NORONHA; LARS ANDERSSON; PER MILBERG

1997-01-01

441

Rate of Change in Dormancy Level and Light Requirement in Weed Seeds During Stratification  

Microsoft Academic Search

The rate of change in dormancy level and light requirement, induced during stratification at 3-2 ?C, was investigated in seeds of Stellaria media, Cerastium fontanum, Veronica agrestis and Taraxacum ocinale. Two stratification environments, soil and wet filter paper in petri-dishes, were used. On nine occasions during a 6 week stratification period, germination was tested under three light conditions at 3-5}18-5

ANGELA N ORONHA; L ARS; P ER M ILBERG

442

Dormancy release and seed ageing in the endangered species Silene diclinis  

Microsoft Academic Search

The influence of seed testa color, temperature and seed water content on dormancy release and seed viability loss in the endangered,\\u000a endemic species Silene diclinis (Lag.) M. Laínz was evaluated. Dormant heterogeneous seeds (black, red and grey colored) were exposed to three different\\u000a temperatures (5, 20, and 35°C) and two relative humidities (33 and 60%) in order to assay their

Sara Mira; M. Elena González-Benito; Ana M. Ibars; Elena Estrelles

2011-01-01

443

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

PubMed

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. PMID:24941250

Staszak, Aleksandra Maria; Paw?owski, Tomasz Andrzej

2014-01-01

444

Proteomic Analysis of Embryogenesis and the Acquisition of Seed Dormancy in Norway Maple (Acer platanoides L.)  

PubMed Central

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. PMID:24941250

Staszak, Aleksandra Maria; Paw?owski, Tomasz Andrzej

2014-01-01

445

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

PubMed

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. PMID:25606408

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

446

Increased ABA sensitivity results in higher seed dormancy in soft white spring wheat cultivar 'Zak'.  

PubMed

As a strategy to increase the seed dormancy of soft white wheat, mutants with increased sensitivity to the plant hormone abscisic acid (ABA) were identified in mutagenized grain of soft white spring wheat "Zak". Lack of seed dormancy is correlated with increased susceptibility to preharvest sprouting in wheat, especially those cultivars with white kernels. ABA induces seed dormancy during embryo maturation and inhibits the germination of mature grain. Three mutant lines called Zak ERA8, Zak ERA19A, and Zak ERA19B (Zak ENHANCED RESPONSE to ABA) were recovered based on failure to germinate on 5 ?M ABA. All three mutants resulted in increased ABA sensitivity over a wide range of concentrations such that a phenotype can be detected at very low ABA concentrations. Wheat loses sensitivity to ABA inhibition of germination with extended periods of dry after-ripening. All three mutants recovered required more time to after-ripen sufficiently to germinate in the absence of ABA and to lose sensitivity to 5 ?M ABA. However, an increase in ABA sensitivity could be detected after as long as 3 years of after-ripening using high ABA concentrations. The Zak ERA8 line showed the strongest phenotype and segregated as a single semi-dominant mutation. This mutation resulted in no obvious decrease in yield and is a good candidate gene for breeding preharvest sprouting tolerance. PMID:23212773

Schramm, Elizabeth C; Nelson, Sven K; Kidwell, Kimberlee K; Steber, Camille M

2013-03-01

447

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

PubMed Central

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. PMID:25606408

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

2014-01-01

448

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

SciTech Connect

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.

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

2010-11-16

449

Dormancy of Cancer Cells with Suppression of AKT Activity Contributes to Survival in Chronic Hypoxia  

PubMed Central

A hypoxic microenvironment in tumors has been recognized as a cause of malignancy or resistance to various cancer therapies. In contrast to recent progress in understanding the acute response of cancer cells to hypoxia, the characteristics of tumor cells in chronic hypoxia remain elusive. We have identified a pancreatic cancer cell line, AsPC-1, that is exceptionally able to survive for weeks under 1% oxygen conditions while most tested cancer cell lines die after only some days under these conditions. In chronic hypoxia, AsPC-1 cells entered a state of dormancy characterized by no proliferation, no death, and metabolic suppression. They reversibly switched to active status after being placed again in optimal culture conditions. ATP turnover, an indicator of energy demand, was markedly decreased and accompanied by reduced AKT phosphorylation. Forced activation of AKT resulted in increased ATP turnover and massive cell death in vitro and a decreased number of dormant cells in vivo. In contrast to most cancer cell lines, primary-cultured colorectal cancer cells easily entered the dormant status with AKT suppression under hypoxia combined with growth factor–depleted conditions. Primary colorectal cancer cells in dormancy were resistant to chemotherapy. Thus, the ability to survive in a deteriorated microenvironment by entering into dormancy under chronic hypoxia might be a common property among cancer cells. Targeting the regulatory mechanism inducing this dormant status could provide a new strategy for treating cancer. PMID:24905002

Endo, Hiroko; Okuyama, Hiroaki; Ohue, Masayuki; Inoue, Masahiro

2014-01-01

450

Ethylene Production is Associated with Germination but not Seed Dormancy in Red Rice  

PubMed Central

Background and Aims The relationship between ethylene production and both seed dormancy and germination was investigated using red rice (weedy rice) as a model species. Methods Both fully dormant and after-ripened (non-dormant) naked caryopses were incubated with or without inhibitors of ethylene synthesis [aminoethoxyvinylglycine (AVG)] and perception [silver thiosulfate (STS)], or in the presence of the natural ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC). The kinetics of ethylene emissions were measured with a sensitive laser–photoacoustic system. Key Results Dormant red rice caryopses did not produce ethylene. In non-dormant caryopses, ethylene evolution never preceded the first visible stage of germination (pericarp splitting), and ethylene inhibitors completely blocked ethylene production, but not pericarp splitting. Accordingly, endogenous ACC appeared to be lacking before pericarp splitting. However, early seedling growth (radicle or coleoptile attaining the length of 1 mm) followed ethylene evolution and was delayed by the inhibitors. Wounding the dormant caryopses induced them to germinate and produce ethylene, but their germination was slow and pericarp splitting could be speeded up by ethylene. Conclusions The findings suggest that, in red rice, endogenous ethylene stimulates the growth of the nascent seedling, but does not affect seed dormancy or germination inception. Correspondingly, this phytohormone does not play a role in the dormancy breakage induced by wounding, but accelerates germination after such breakage has occurred. PMID:17347162

Gianinetti, Alberto; Laarhoven, Lucas J. J.; Persijn, Stefan T.; Harren, Frans J. M.; Petruzzelli, Luciana

2007-01-01

451

What Prolongs a Butterfly's Life?: Trade-Offs between Dormancy, Fecundity and Body Size  

PubMed Central

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. PMID:25390334

Haeler, Elena; Fiedler, Konrad; Grill, Andrea

2014-01-01

452

Wax Ester Synthesis is Required for Mycobacterium tuberculosis to Enter In Vitro Dormancy  

PubMed Central

Mycobacterium tuberculosis (Mtb) is known to produce wax esters (WE) when subjected to stress. However, nothing is known about the enzymes involved in biosynthesis of WE and their role in mycobacterial dormancy. We report that two putative Mtb fatty acyl-CoA reductase genes (fcr) expressed in E. coli display catalytic reduction of fatty acyl-CoA to fatty aldehyde and fatty alcohol. Both enzymes (FCR1/Rv3391) and FCR2/Rv1543) showed a requirement for NADPH as the reductant, a preference for oleoyl-CoA over saturated fatty acyl-CoA and were inhibited by thiol-directed reagents. We generated Mtb gene-knockout mutants for each reductase. Metabolic incorporation of 14C-oleate into fatty alcohols and WE was severely diminished in the mutants under dormancy-inducing stress conditions that are thought to be encountered by the pathogen in the host. The fatty acyl-CoA reductase activity in cell lysates of the mutants under nitric oxide stress was significantly reduced when compared with the wild type. Complementation restored the lost activity completely in the ?fcr1 mutant and partially in the ?fcr2 mutant. WE synthesis was inhibited in both ?fcr mutants. The ?fcr mutants exhibited faster growth rates, an increased uptake of 14C-glycerol suggesting increased permeability of the cell wall, increased metabolic activity levels and impaired phenotypic antibiotic tolerance under dormancy-inducing combined multiple stress conditions. Complementation of the mutants did not restore the development of antibiotic tolerance to wild-type levels. Transcript analysis of ?fcr mutants showed upregulation of genes involved in energy generation and transcription, indicating the inability of the mutants to become dormant. Our results indicate that the fcr1 and fcr2 gene products are involved in WE synthesis under in vitro dormancy-inducing conditions and that WE play a critical role in reaching a dormant state. Drugs targeted against the Mtb reductases may inhibit its ability to go into dormancy and therefore increase susceptibility of Mtb to currently used antibiotics thereby enhancing clearance of the pathogen from patients. PMID:23272127

Sirakova, Tatiana D.; Deb, Chirajyoti; Daniel, Jaiyanth; Singh, Harminder D.; Maamar, Hedia; Dubey, Vinod S.; Kolattukudy, Pappachan E.

2012-01-01

453

Copyright 2000 by the Genetics Society of America Quantitative Trait Loci and Candidate Gene Mapping of Bud Set  

E-print Network

Mapping of Bud Set and Bud Flush in Populus Barbara E. Frewen,* Tony H. H. Chen, Glenn T. Howe, Joel Davis- related traits in the F2 generation--the female Populus trichocarpa parent is from Washington State (48 N) and the male P. deltoides parent is from Texas (31 N). Bud set and bud flush timing were measured on the F2

Bradshaw, Toby

454

Bloodcount returns to normal with Gleevec, Bud and YvonneSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

Interviewee: Bud and Yvonne DNAi Location:Applications>Genes and medicine>drug design>Bud's Story>A Breakthrough A breakthrough CML causes an increased production of white blood cells. Bud and Yvonne talk about the breakthrough that brought Bud's white blood cell count back to normal.

2008-03-26

455

The Impact of Kindergarten Entrance Age Policies on the Childcare Needs of Families  

ERIC Educational Resources Information Center

The past two decades have seen a rising trend in the minimum entrance age for kindergarten in the U.S. A little-noticed, but potentially large, consequence of raising the minimum entrance age is that it imposes additional childcare costs for families whose children are forced to stay out of school for an additional year. This paper develops a…

Datar, Ashlesha

2006-01-01

456

Proposals for Standardizing and Improving the Policy of Adding Points on the Entrance Exam  

ERIC Educational Resources Information Center

This article reviews policies for adding points on the College Entrance Examination. It analyzes the rationales and specific implementation strategies of various policies for adding points on the entrance exam, as well as their advantages and pitfalls. Based on these observations and analysis, the author also offers policy recommendations on the…

Yuhong, Deng

2013-01-01

457

Hillsborough County Courthouse Annex, 800 East Kennedy Boulevard, Tampa, Fla., east entrance  

Microsoft Academic Search

The brick stair-towers are banded to reveal the floor lines. The first-floor ceiling\\/roof floats on a narrow window strip and forms a visual platform jutting out and cantilevered over the entrance. This is the east entrance.

Sape A. Zylstra

2010-01-01

458

The distribution of taste buds in Garra rufa.  

PubMed

The distribution and relative frequency of external taste buds (TB) of Garra rufa were studied. TB of Garra rufa were observed on different body location (lips, lateral and ventral areas, forehead, operculum and dorsal-pelvic-pectoral-anal fins). TB are at the highest frequency in lips, forehead, pectoral and anal fins. These structures are moderate as a number in operculum, La2 (between pelvic and anal fins) areas, and then decreased a few in other areas. PMID:18197902

Cinar, K; Senol, N; Kuru, N

2008-02-01

459

Part 2: Details of DNA Repair in Budding Yeast  

NSDL National Science Digital Library

A specific set of examples of homologous recombination in budding yeast is presented based primarily on data from the Haber lab. Here a site-specific HO endonuclease can be induced to create a single DSB in the genome and the kinetics of repair can be followed in real time. The roles of key recombination proteins and the different types of outcomes provoked by this DSB are reviewed.

Jim Haber (Brandeis University;Department of Biology and Rosenstiel Basic Medical Sciences Research Center)

2009-12-01

460

Electron Tomography Reveals the Steps in Filovirus Budding  

Microsoft Academic Search

The filoviruses, Marburg and Ebola, are non-segmented negative-strand RNA viruses causing severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. The sequence of events that leads to release of filovirus particles from cells is poorly understood. Two contrasting mechanisms have been proposed, one proceeding via a “submarine-like” budding with the helical nucleocapsid emerging parallel to the plasma

Sonja Welsch; Larissa Kolesnikova; Verena Krähling; James D. Riches; Stephan Becker; John A. G. Briggs

2010-01-01