Tag germination [88 articles]

Abstract

Food mixtures formulated from non-germinated and germinated barley flour, whey powder and tomato pulp (2:1:1w/w) were autoclaved, cooled and fermented with 5% Lactobacillus acidophilus curd (10 6  cells/ml) at 37 °C for 12 h. The cell count was found significantly higher (8.88 cfu/g) in the fermented food mixture formulated from germinated flour as compared to the non-germinated barley based food mixture. A significant drop in pH with corresponding increase in titratable acidity was found in the germinated barley flour based food mixture. Processing treatments ...

Abstract

In an effort to better understand the mechanisms by which Bacillus anthracis establishes disease, experiments were undertaken to identify the genes essential for intracellular germination. Eighteen diverse genetic loci were identified via an enrichment protocol using a transposon-mutated library of B. anthracis spores, which was screened for mutants delayed in intracellular germination. Fourteen transposon mutants were identified in genes not previously associated with B. anthracis germination and included disruption of factors involved in membrane transport, transcriptional regulation, and intracellular signaling. Four ...

Abstract

Abstract  While screening for genes affected by cold, we found that Early Responsive to Dehydration 10 (ERD10) was induced by cold treatment. To further investigate the physiological functions of ERD10, we analyzed the T-DNA insertion mutant of ERD10 as well as the expression of ERD10 in response to various stress conditions. The erd10 mutant showed reduced stress tolerance relative to wild-type plants. Activation of the CBF/DREB1 genes by cold stress did not occur in the erd10 mutant, indicating that an increased level ...

Abstract

10.1098/rspb.2009.0592 Seed germination is the first adaptive decision in the development of many land plants. Advances in genetics and molecular physiology have taught us much about the control of germination using the model plant . Here we review the current state of the art with an emphasis on mechanistic considerations and explore the potential impact of a systems biology approach to the problem. ...

Abstract

The influence of number of seeds per clump upon germination of Plantago coronopus L. was investigated at different salinity levels on filter paper, sand and soil. These substrates provide both artificial and semi-natural microenvironments for seed germination. On all substrates, germination was positively dependent on clump density and seeds in clumps had a higher tolerance of salinity as reflected in higher germination percentages. Final percentage germination for a given clump size and salinity level depended upon substrate, being far higher on ...

Abstract

Field observations and experiments indicate that the presence of seedlings at high densities inhibits subsequent germination of desert annuals. Since plants growing at high densities face severe competition for limited resources, this response by seeds is interpreted as an adaptation to avoid an unfavorable competitive climate where growth and survivorship are likely to be low. ...

Abstract

Studying germination in the native and non-native range of a species can provide unique insights into processes of range expansion and adaptation; however, traits related to germination have rarely been compared between native and non-native populations. In a series of common garden experiments, we explored whether differences in the seasonality of precipitation, specifically, summer drought vs summer rain, and the amount and variation of annual and seasonal precipitation affect the germination responses of populations of an annual ruderal plant, Centaurea solstitialis, ...

Abstract

We tested whether increasing seed density results in a change in the timing of emergence in two communities of sand dune annual plants in Israel. Specifically we tested (i) if emergence is accelerated or delayed due to high seed density. We also tested two predictions about the consequences of changes in the timing of emergence; (ii) seedlings emerging earlier will have higher survival and growth; (iii) the advantage of earlier emergence increases as seed density increases. We examined these predictions for ...

Abstract

Annual plants in unpredictable environments maintain dormant seeds to avoid extinction. Here, we present results for four desert annual species suggesting that germination rates are variable even in the absence of abiotic cues. Namely, seeds produced in a copious year had lower germination rates than seeds produced in drought years. Inspired by our data, we have extended previous bet-hedging models by including a structured seed bank. With density-dependence, the ESS (environmental stable strategy) involved a negative relationship between seed yield and ...

Abstract

Seeds of eleven species of plants were germinated singly or in groups to assay the effect of density on germination. Literature reports on eleven more species are also considered. Of fifteen colonizing species, seven show a negative response, seven no response, and one (also grown as a crop) a positive response. Four of the six non-colonizing species and one forage species show a positive response. Reduced germination at high densities may be a population-regulating mechanism. Increased germination may increase the probability ...

Abstract

Germination in light and darkness was compared after cold stratification of seeds of 54 species known or suspected to accumulate persistent seed banks. Germination became less dependent on light with increasing seed mass. This pattern was clear in a direct correlation of individual species data (P <0.0001) as well as when considering phylogenetically independent contrasts (P <0.001). The latter analysis suggests that light response and seed mass coevolved. ...

Abstract

This review focuses mainly on eudicot seeds, and on the interactions between abscisic acid (ABA), gibberellins (GA), ethylene, brassinosteroids (BR), auxin and cytokinins in regulating the interconnected molecular processes that control dormancy release and germination. Signal transduction pathways, mediated by environmental and hormonal signals, regulate gene expression in seeds. Seed dormancy release and germination of species with coat dormancy is determined by the balance of forces between the growth potential of the embryo and the constraint exerted by the covering layers, ...

Abstract

Weeds play an important role in arable and horticultural habitats, and models are being developed to improve our understanding of their population dynamics. The position of a weed seed in the soil profile influences the probability of a seed germinating, emerging successfully and its relative time of emergence. Identifying a relationship between the shape or weight of a seed and its ability to emerge from depth may allow the development of generic models. The aim of this study was to quantify ...

Abstract

Summary  501 Introduction  502 What is dormancy and how is it related to germination?  502 How is nondeep physiological dormancy regulated within the seed at the molecular level?  509 How is nondeep physiological seed dormancy regulated by the  environment? Ecophysiology and modelling  514 Conclusions and perspectives  518 Acknowledgements  519 References  519 Supplementary material  523 Seed dormancy is an innate seed property that defines the environmental conditions in which the seed is able to germinate. It is determined by genetics with a substantial environmental influence which is mediated, at least in ...

Abstract

The effects of cold stratification, light and seed clustering in petri dish on Ottelia alismoides seed germination were investigated. The seeds required light and an extended cold period in order to germinate, but neither treatment alone was effective. Seed germination significantly increased with length of the 4 °C cold stratification period. Freshly collected seeds failed to germinate while a 5-month period at 4 °C yielded 29 ± 9% germination in the light, but none in the dark. Treatment with sodium nitroprusside, a nitric ...

Abstract

The timing of seedling emergence may strongly affect fitness in competitive environments. Therefore, selection should favour mechanisms that allow sensing neighbours prior to emergence. We tested whether or not germination is affected by density and identity of neighbouring seeds or seedlings of desert perennial plants. Based on theory, we predicted that germination fractions are independent of neighbouring seeds, that germination is accelerated in dense interspecific neighbourhoods, and neighbour effects are caused by seedlings, not by seeds. We examined germination fraction and ...

Abstract

Seed size and germination requirements of eight (of nine) Sarracenia species, and 13 populations of S. purpurea were studied. All species except for S. purpurea are restricted to the southeastern United States, whereas S. purpurea ranges across Canada, southward along the eastern United States into Maryland and Virginia (S. purpurea ssp. purpurea), and from New Jersey southward into northern Florida and the coast of the Gulf of Mexico (S. purpurea ssp. venosa). I tested the hypotheses that dormancy-breaking requirements ...

Abstract

Clostridium perfringens type A isolates carrying a chromosomal copy of the enterotoxin (cpe) gene are involved in the majority of food poisoning (FP) outbreaks, while type A isolates carrying a plasmid-borne cpe gene are involved in C. perfringens-associated non-food-borne (NFB) gastrointestinal diseases. To cause diseases, C. perfringens spores must germinate and return to active growth. Previously, we showed that only spores of FP isolates were able to germinate with K+ ions. We now found that the spores of the majority of ...

Abstract

The genome of the Clostridium perfringens food poisoning isolate SM101 encodes a subtilisin-like protease, CspB, upstream of the sleC gene encoding the enzyme essential for degradation of the peptidoglycan cortex during spore germination. SleC is an inactive pro-SleC in dormant spores that is converted to active SleC during spore germination and Csp proteases convert pro-SleC to the active enzyme in vitro. In this work, the germination and viability of spores of a cspB deletion mutant of strain SM101, as well as ...

Abstract

The interactions between seeds in the soil are poorly understood. We performed greenhouse experiments to investigate the effects of seed density, relative frequency, and relative planting date on the emergence of seedlings in the species Senecio vulgaris, Capsella bursa-pastoris, and Poa annua. We found that for both Poa and Senecio, the probability of emergence significantly decreased with an increase in total seed density. Neither the density of conspecifics nor heterospecifics alone could explain this decline in the probability of emergence. We ...

Abstract

Lutman PJW, Berry KJ & Freeman SE (2008). Seed production and subsequent seed germination of Senecio vulgaris (groundsel) grown alone or in autumn-sown crops. Weed Research48, 2372013247. Senecio vulgaris is a common weed of agriculture in the UK, but is also of food value to invertebrates and birds. Thus, it may be beneficial to retain it within agricultural ecosystems to enhance overall biodiversity. A less intensive approach to weed management requires a sound understanding of weed population dynamics so as to ...

Abstract

A comparative structure-activity relationship (SAR) study has been conducted with several guaianolide sesquiterpene lactones (SLs) as inducers of the germination of sunflower broomrape (Orobanche cumana) seeds. Compounds were selected and synthesized to study the influence of the lactone-enol-gamma-lactone moiety on the selectivity of SLs toward the stimulation of sunflower broomrape germination. The results clearly illustrate that SLs are recognized only by O. cumana, while the introduction of a strigol-like second lactone moiety in the guaianolide backbone results in the loss of ...

Abstract

Summary  A number of parasitic plants have become weeds, posing severe constraints to major crops including grain legumes. Breeding for resistance is acknowledged as the major component of an integrated control strategy. However, resistance against most parasitic weeds is difficult to access, scarce, of complex nature and of low heritability, making breeding for resistance a difficult task. As an exception, resistance against Striga gesnerioides based on a single gene has been identified in cowpea and widely exploited in breeding. In other crops, ...

Abstract

PMID: 11902932 Studies of the structureactivity relationship (SAR) directed to evaluate the effect of several sesquiterpene lactones (SL) as germination stimulants of three Orobanche spp. (O. cumana, O. crenata, and O. ramosa) have been achieved. Results are compared with those obtained in the same bioassay with an internal standard, the synthetic analogue of strigol GR-24. A high specificity in the germination activity of SL on the sunflower parasite O. cumana has been observed, and a relationship between such activity and the ...

Abstract

The interaction of the parasitic plant Orobanche cernua with resistant and susceptible cultivars of Helianthus annuus L. was investigated. Using different bioassays to evaluate the early stages of the parasite life cycle (germination, attachment, penetration, and establishment), differences were observed between O. cernua-resistant and O. cernua-susceptible sunflower varieties. Germination of O. cernua seeds in the presence of resistant sunflower roots was approximately half that of germination in the presence of susceptible roots, and germinated seeds displayed enhanced browning symptoms. Parasite radicles ...

Abstract

OBJECTIVE AND DESIGN: Food grains such as green gram, chickpea and finger millet are often subjected to traditional processing involving germination and fermentation. This study was designed to assess the effect of germination of these grains on the bioaccessibility of zinc and iron. The effect of fermentation of a cereal-pulse combination as encountered in the preparation of breakfast dishes - idli, dosa and dhokla - on the same was also evaluated. Bioaccessibility measurement was made employing an in vitro simulated digestion ...

Abstract

Question: Is primary dormancy required for seed bank persistence of Leucopogon species? How does the distinction between dormancy and persistence affect our understanding of seed bank dynamics in fire-prone regions? Location: Sclerophyllous plant communities, Sydney region, southeastern Australia. Methods: Seed bank longevity of three morphophysiologically dormant species was ascertained using seed burial trials. Seeds of each species were buried in situ in replicate mesh bags and retrieved annually over three years. Laboratory germination trials and embryo growth measurements over time were used to ...

Abstract

Dormant Bacillus subtilis spores can be induced to germinate by nutrients, as well as by nonmetabolizable chemicals, such as a 1:1 chelate of Ca(2+) and dipicolinic acid (DPA). Nutrients bind receptors in the spore, and this binding triggers events in the spore core, including DPA excretion and rehydration, and also activates hydrolysis of the surrounding cortex through mechanisms that are largely unknown. As Ca(2+)-DPA does not require receptors to induce spore germination, we asked if this process utilizes other proteins, such ...

Abstract

The predicted amino acid sequence of Bacillus subtilis ycbQ (renamed cwlJ) exhibits high similarity to those of the deduced C-terminal catalytic domain of SleBs, the specific cortex-hydrolyzing enzyme of B. cereus and the deduced one of B. subtilis. We constructed a cwlJ::lacZ fusion in the B. subtilis chromosome. The beta-galactosidase activity and results of Northern hybridization and primer extension analyses of the cwlJ gene indicated that it is transcribed by EsigmaE RNA polymerase. cwlJ-deficient spores responded to both L-alanine and AGFK, ...

Abstract

The germination of dormant spores of Bacillus species is the first crucial step in the return of spores to vegetative growth, and is induced by nutrients and a variety of non-nutrient agents. Nutrient germinants bind to receptors in the spore's inner membrane and this interaction triggers the release of the spore core's huge depot of dipicolinic acid and cations, and replacement of these components by water. These latter events trigger the hydrolysis of the spore's peptidoglycan cortex by either of two ...

Abstract

Clostridium perfringens food poisoning is caused by type A isolates carrying a chromosomal enterotoxin (cpe) gene (C-cpe), while C. perfringens-associated non-food-borne gastrointestinal (GI) diseases are caused by isolates carrying a plasmid-borne cpe gene (P-cpe). C. perfringens spores are thought to be the important infectious cell morphotype, and after inoculation into a suitable host, these spores must germinate and return to active growth to cause GI disease. We have found differences in the germination of spores of C-cpe and P-cpe isolates in ...

Abstract

Clostridium difficile is an emerging nosocomial pathogen and one of the major causes of antibiotic-associated diarrhoea. Cases of Clostridium difficile-associated disease (CDAD) are likely initiated by the ingestion of dormant C. difficile spores, which then germinate, outgrow and rapidly proliferate to cause gastrointestinal (GI) infections. To understand the initial stages of CDAD pathogenesis, we have characterized the germination of spores from a collection of C. difficile strains, including some clinical isolates obtained from a CDAD outbreak (CDAD isolates). Spores of one ...

Abstract

Previous work indicated that Clostridium perfringens gerKA gerKC spores germinate significantly, suggesting that gerKB also has a role in C. perfringens spore germination. We now find that (i) gerKB was expressed only during sporulation, likely in the forespore; (ii) gerKB spores germinated like wild-type spores with nonnutrient germinants and with high concentrations of nutrients but more slowly with low nutrient concentrations; and (iii) gerKB spores had lower colony-forming efficiency and slower outgrowth than wild-type spores. These results suggest that GerKB plays ...

Abstract

The genome of the pathogen Clostridium perfringens encodes two proteins, GerO and GerQ, homologous to monovalent cation transporters suggested to have roles in the germination of spores of some Bacillus species. GerO and GerQ were able to transport monovalent cations (K(+) and/or Na(+)) in Escherichia coli, and gerO and gerQ were expressed only in the mother cell compartment during C. perfringens sporulation. C. perfringens spores lacking GerO were defective in germination with a rich medium, KCl, L-asparagine, and a 1:1 chelate ...

Abstract

Clostridial spore germination requires degradation of the spore's peptidoglycan (PG) cortex by cortex-lytic enzymes (CLEs), and two Clostridium perfringens CLEs, SleC and SleM, degrade cortex PG in vitro. We now find that only SleC is essential for cortex hydrolysis and viability of C. perfringens spores. C. perfringens sleC spores did not germinate completely with nutrients, KCl, or a 1:1 chelate of Ca(2+) and dipicolinic acid (Ca-DPA), and the colony-forming efficiency of sleC spores was 10(3)-fold lower than that of wild-type spores. ...

Abstract

Spore formation by Clostridium difficile is a significant obstacle to overcoming hospital-acquired C. difficile-associated disease. Spores are resistant to heat, radiation, chemicals, and antibiotics, making a contaminated environment difficult to clean. To cause disease, however, spores must germinate and grow out as vegetative cells. The germination of C. difficile spores has not been examined in detail. In an effort to understand the germination of C. difficile spores, we characterized the response of C. difficile spores to bile. We found that cholate ...

Abstract

Clostridium tyrobutyricum is an anaerobic bacterium responsible for late blowing defects during cheese ripening and it is of scientific interest for biological hydrogen production. A scanning electron microscopy (SEM) coating technique and X-ray microanalysis were developed to analyze the architecture and chemical composition of spores upon germination in response to environmental changes. In addition, we investigated the effects of different compounds on this process. Agents and environmental conditions inducing germination were characterized monitoring changes in optical density (OD). Among all tested ...

Abstract

PHYTOCHROME INTERACTING FACTOR 3-LIKE5 (PIL5) is a basic helix-loop-helix transcription factor that inhibits seed germination by regulating the expression of gibberellin (GA)- and abscisic acid (ABA)-related genes either directly or indirectly. It is not yet known, however, whether PIL5 regulates seed germination solely through GA and ABA. Here, we used Chromatin immunoprecipitation-chip (ChIP-chip) analysis to identify 748 novel PIL5 binding sites in the Arabidopsis thaliana genome. Consistent with the molecular function of PIL5 as a transcription regulator, most of the identified ...

Abstract

Abstract  Fire is an ecological factor that has been present in the ecosystems of the Mediterranean region for thousands of years. Our study was undertaken to acquire knowledge of the effect of fire on the germination of Mediterranean species. We used high temperatures (up to 60°C) and smoke to determine the effect of these factors on the germination of species from the Mediterranean region. The species selected are characteristic of the central Mediterranean basin and are representative of both woody and herbaceous ...

Abstract

Abstract  Vegetative resprouting, soil or canopy-stored seed banks, post-fire seed dispersal and germination are the major strategies by which plants regenerate after fires. Post-fire regeneration modes of plants are commonly based on the presence or absence of post-fire recruitment as well as the presence or absence of post-fire resprouting. High temperatures, smoke and ash are characteristics of fire and the post-fire environment. We hypothesized that heat, smoke, ash and pH will have differential effects on seed germination depending on species’ post-fire regeneration ...

Abstract

In this study we determined the effects of incubation temperature and prior heat-treatment on the lag phase kinetics of individual spores of nonproteolytic Clostridium botulinum Eklund 17B. Times to germination (tgerm), one mature cell (tC1) and two mature cells (tC2) were measured for individual unheated spores incubated at 8degrees, 10degrees, 15degrees or 22degreesC, and used to calculate germination (tgerm), outgrowth (tC1-tgerm) and first doubling time (tC2-tC1). Measurements were also made at 22degreesC of spores that had previously been heated at 80degreesC ...

Abstract

Methyl jasmonate (JA-Me) at 10-3Minhibited Amaranthus caudatus seed germination anddecreased a-amylase activity. Exogenous gibberellin A3(GA3) and ethylene, but not benzyladenine (BA), increased activity ofthe enzyme in the presence of JA-Me, with ethylene being the most effective. Theinhibitor of ethylene action, 2,5-norbornadiene (NBD) inhibited seed germinationand decreased a-amylase activity. The inhibitory action of JA-Me onAmaranthus caudatus seed germination is associated with theinhibition of a-amylase activity. Exogenous GA3 and ethylenecontrol both a-amylase activity and seed germination in the presence of JA-Me. ...

Abstract

Seven experiments were conducted in incubators to determine the effects of several factors on the germination of two amaranth cultivars. Investigated factors were year of harvest, crop type of the mother plant, seed position on the mother plant, stage of maturity, temperature, light, and seed dressing. Percentage germination and germination speed were recorded. Most effects appeared in interaction with cultivars. Percentage germination was above 80% with temperatures higher than 16°C. The germination speed was closely related to temperature and decreased with ...