Quantifying the oxygen sensitivity of seed germination using a population-based threshold model

2007 ◽  
Vol 17 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Kent J. Bradford ◽  
Daniel Côme ◽  
Françoise Corbineau
Keyword(s):  
Standard Deviation ◽  
Seed Germination ◽  
Time Constant ◽  
Threshold Model ◽  
Seed Priming ◽  
Population Based ◽  
Physiological Status ◽  
Wide Range ◽  
Time Courses ◽  
Germination Timing

AbstractSeeds vary widely in the sensitivity of germination to oxygen (O2) partial pressure, depending upon the species, temperature, dormancy state and physiological status of the seeds. Most analyses of the O2 sensitivity of germination have focused on final germination percentages and estimated the O2 percentage in air that is required to reduce germination to a given percentage (usually 50%). In contrast, we have applied a population-based threshold model utilizing time courses of germination to quantify three parameters related to seed germination sensitivity to O2 availability: the median base (or threshold) O2 percentage, the standard deviation of O2 thresholds among seeds in the population, and an oxygen–time constant that relates O2 percentage to germination timing. The model fits germination responses accurately across a wide range of O2 concentrations. The response to O2 was logarithmic in all cases, with the O2 percentage required for 50% germination ranging from 21% to as low as 0.005%, depending upon the species, the temperature and the seed dormancy level. Modelling indicated that some seeds can adapt to low O2 percentages and shift their thresholds to lower values over time. Lower temperatures decreased the minimum O2 threshold, as did after-ripening. Seed priming generally reduced the oxygen–time constant and increased the standard deviation of germination responses, but had relatively little effect on the O2 sensitivity per se. The population-based threshold model can be used to quantify the O2 sensitivity of seed germination and to predict germination rates and percentages when O2 availability is limiting.

scholarly journals ABSCISIC ACID AND WATER RELATIONS MODELS OF SEED GERMINATION.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1093e-1093
Author(s):  
Bing-Rui Ni ◽  
Kent J. Bradford
Keyword(s):  
Standard Deviation ◽  
Seed Germination ◽  
Osmotic Stress ◽  
Water Relations ◽  
Growth Models ◽  
Probit Analysis ◽  
Population Characteristics ◽  
Germination Time ◽  
The Mean ◽  
Time Courses

Cell growth models were applied to characterize the response of seed germination, based upon the timing of radicle emergence, to y and ABA. Using probit analysis, three basic parameters can be derived to describe the population characteristics of seed lots. In the response of seed germination to osmotic stress, these three parameters are the “hydrotime constant” (q H), the mean base water potential (y b), and the standard deviation (s b) population. In the response to ABA, they are the “ABA-time constant” (q ABA), the mean base ABA concentration (ABAb), and the standard deviation (s ABAb) of the seed population. Using only these three parameters, germination time courses can be predicted at any corresponding medium y or ABA concentration. In the presence of both ABA and osmotic stress, the same parameters can be used to predict seed germination time courses with any combination of y and ABA concentration. The water relations model and the ABA model were additive and it appeared that the two factors slowed down germination independently. Effects of osmotic stress and ABA on the parameters in Lockhart equation are also discussed.

Patterns of amplified restriction fragment polymorphism in the germination of Festuca hallii seeds

2010 ◽  
Vol 20 (3) ◽  
pp. 153-161
Author(s):  
Jie Qiu ◽  
Yuguang Bai ◽  
Yong-Bi Fu ◽  
John F. Wilmshurst
Keyword(s):  
Genetic Variation ◽  
Seed Germination ◽  
Genetic Differentiation ◽  
Restriction Fragment ◽  
Population Based ◽  
Canadian Prairie ◽  
Band Frequency ◽  
Restriction Fragment Polymorphism ◽  
Festuca Hallii ◽  
Germination Timing

AbstractTiming of seed germination influences plant lifetime fitness and can affect the ability of plant populations to colonize and persist in changing environments. However, the genetic variation of the seed germination response remains poorly understood. The amplified restriction fragment polymorphism (AFLP) technique was applied to characterize the genetic variation of germinated seeds collected from three Festuca hallii populations in the Canadian prairie. Three subpopulations with early, intermediate and late germination were identified from each population, based on germination tests at 10, 15 and 20°C in controlled growth chambers. Three AFLP primer pairs were employed to screen a total of 540 assayed seedling samples and 188 polymorphic AFLP bands were scored for each sample. None of the assayed AFLP bands were significantly associated with seed germination, but marked differences in estimates of mean band frequency were observed for various groups of germinating seeds under different test temperatures. Partitioning of the total AFLP variation showed that 5.9% AFLP variation was present among seeds of the three populations, 0.3% among seeds of three germination subpopulations, and 0.5% among seeds grouped for germination temperature. Genetic differentiation was significant among 27 groups of seeds representing population, germination timing and test temperature. Subpopulations with early and intermediate germination shared similar genetic backgrounds and were genetically differentiated from the late germination subpopulation. These results indicate that seed genotypes respond slightly differently to environmental variation, resulting in significant but weak genetic differentiation in the germination of F. hallii seeds. Implications for plant establishment and fescue restoration are discussed.

scholarly journals Quantifying the sensitivity of barley seed germination to oxygen, abscisic acid, and gibberellin using a population-based threshold model

2008 ◽  
Vol 59 (2) ◽  
pp. 335-347 ◽  
Author(s):  
Kent J. Bradford ◽  
Roberto L. Benech-Arnold ◽  
Daniel Côme ◽  
Françoise Corbineau
Keyword(s):  
Abscisic Acid ◽  
Seed Germination ◽  
Threshold Model ◽  
Population Based ◽  
Barley Seed

scholarly journals Seed Germination for Transplants

1998 ◽  
Vol 8 (4) ◽  
pp. 499-503 ◽  
Author(s):  
Daniel J. Cantliffe
Keyword(s):  
Seed Germination ◽  
Relative Humidity ◽  
Seed Quality ◽  
Seed Priming ◽  
Film Coating ◽  
Economic Success ◽  
Crop Species ◽  
Wide Range ◽  
Total Plant

Seed germination is a critical step to achieve economic success in a transplant operation. Total germination of a seed lot dictates total plant sales by the producer, while uniformity of germination dictates the quality of the transplant crop. Using high vigor seed will help to achieve uniform stands, as well as maximize stands, in the transplant house or field. In order to maintain the highest seed quality, transplant producers should store unused seeds at recommended temperature and relative humidity for the crop species. Methods to promote uniformity and optimum stands under a wide range of conditions include the use of seed priming, film coating with fungicides, and pelleting for ease of planting.

​Physiological, Biochemical and Molecular Mechanisms of Seed Priming: A Review

2021 ◽  
Author(s):  
A. Diya ◽  
R. Beena ◽  
V.G. Jayalekshmy
Keyword(s):  
Seed Germination ◽  
Molecular Mechanisms ◽  
Seed Quality ◽  
Seedling Emergence ◽  
Cost Effective ◽  
Seed Priming ◽  
Critical Parameters ◽  
High Yield ◽  
Wide Range ◽  
Sowing Seed

Legumes being a major source of protein have a wide range of economic importance. But the major constraints in growing legumes are poor germination, seedling emergence, non uniform stand establishment and crop mortality leading to lower pulse productivity. Thus, pre-sowing seed treatments are critical parameters which attribute to efficient plant growth and high yield. Uniform seed germination, seedling growth and uniform establishment are the critical stages during the growth of crops. Seed priming is a very promising presowing treatment employed to improve seed germination, better crop establishment, enhance the seed quality and induces tolerance against biotic and abiotic stresses in plants thereby providing a balanced healthy diet to the citizens. Priming is a cost effective and feasible strategy involving controlled hydration of seeds followed by drying to stimulate the pre-germinative metabolic activities to occur promoting rapid germination of seedlings, break dormancy and enhance crop yield. Enzymatic, metabolic and biochemical processes of the primed seeds attributes to rapid and uniform seedling emergence. Seed priming methods comprises of conventional methods including hydro priming, osmopriming, biopriming, chemical priming and the advanced methods including nano priming and priming with physical agents. In this review paper, the underlying physiological, biochemical and molecular aspects of priming in pulses were discussed.

Strong Association between Serotonin Transporter 5-HTTVNTR Variant and Psychoactive Substance (Nicotine) Use in the Turkish Cypriot Population

2020 ◽  
Vol 21 (6) ◽  
pp. 466-470
Author(s):  
Emine Kandemis ◽  
Gulten Tuncel ◽  
Ozen Asut ◽  
Sehime G. Temel ◽  
Mahmut C. Ergoren
Keyword(s):  
Serotonin Transporter ◽  
Association Studies ◽  
Strong Association ◽  
Smoking Behavior ◽  
Population Based ◽  
Genome Wide Association Studies ◽  
Genotype Distribution ◽  
Psychological Traits ◽  
Wide Range ◽  
Turkish Cypriot

Background: The use of psychoactive substances is one of the most dangerous social problems worldwide. Nicotine dependence results from the interaction between neurobiological, environmental and genetic factors. Serotonin is a neurotransmitter that has a wide range of central nervous system activities. The serotonin transporter gene has been previously linked to psychological traits. Objective: A variable number of tandem repeats within the serotonin transporter-linked polymorphic gene region are believed to alter the transcriptional efficiency of the 5-HTT gene. Therefore, we aimed to investigate the association between this polymorphic site and smoking behavior in the Turkish Cypriot population. Methods: A total of 259 (100 smokers, 100 non-smokers and 59 ex-smokers) Turkish Cypriots were included in this population-based cross-sectional study. Genomic DNA was extracted from peripheral blood samples and the 5-HTTVNTR2 polymorphisms were determined by the PCR-RFLP. Results: The allelic frequency and genotype distribution results of this study showed a strong association (P<0.0001) between smokers and non-smokers. No statistical significance was found between non-smokers and ex-smokers. Conclusion: This is the first genetic epidemiology study to investigate the allelic frequencies of 5-HTTVNTR2 polymorphisms associated with smoking behavior in the Turkish Cypriot population. Based on the results of this study, genome-wide association studies should be designed for preventive medicine in this population.

scholarly journals Genetic, lifestyle, and health-related characteristics of adults without celiac disease who follow a gluten-free diet: a population-based study of 124,447 participants

2020 ◽  
Author(s):  
Thomas J Littlejohns ◽  
Amanda Y Chong ◽  
Naomi E Allen ◽  
Matthew Arnold ◽  
Kathryn E Bradbury ◽  
...  
Keyword(s):  
Celiac Disease ◽  
Genome Wide Association Study ◽  
Population Based ◽  
Gluten Free Diet ◽  
Hospital Inpatient ◽  
Gluten Free ◽  
A Genome ◽  
Wide Range ◽  
Health Related ◽  
Reported Health

ABSTRACT Background The number of gluten-free diet followers without celiac disease (CD) is increasing. However, little is known about the characteristics of these individuals. Objectives We address this issue by investigating a wide range of genetic and phenotypic characteristics in association with following a gluten-free diet. Methods The cross-sectional association between lifestyle and health-related characteristics and following a gluten-free diet was investigated in 124,447 women and men aged 40–69 y from the population-based UK Biobank study. A genome-wide association study (GWAS) of following a gluten-free diet was performed. Results A total of 1776 (1.4%) participants reported following a gluten-free diet. Gluten-free diet followers were more likely to be women, nonwhite, highly educated, living in more socioeconomically deprived areas, former smokers, have lost weight in the past year, have poorer self-reported health, and have made dietary changes as a result of illness. Conversely, these individuals were less likely to consume alcohol daily, be overweight or obese, have hypertension, or use cholesterol-lowering medication. Participants with hospital inpatient diagnosed blood and immune mechanism disorders (OR: 1.62; 95% CI: 1.18, 2.21) and non-CD digestive system diseases (OR: 1.58; 95% CI: 1.42, 1.77) were more likely to follow a gluten-free diet. The GWAS demonstrated that no genetic variants were associated with being a gluten-free diet follower. Conclusions Gluten-free diet followers have a better cardiovascular risk profile than non-gluten-free diet followers but poorer self-reported health and a higher prevalence of blood and immune disorders and digestive conditions. Reasons for following a gluten-free diet warrant further investigation.

scholarly journals TEMPERATURE - GERMINATION RESPONSES OF SUNFLOWER (Helianthus annuus L.) GENOTYPES / GERMINACION COMO REACCION A LA TEMPERATURA EN LOS GENOTIPOS DEL GIRASOL (Helianthus annuus L.) / GERMINATION - RÉACTION À LA TEMPÉRATURE DANS LES GÉNOTYPES DE TOURNESOL (Helianthus annuus L.)

Helia ◽  
2000 ◽  
Vol 23 (33) ◽  
pp. 97-104
Author(s):  
F.M. Khalifa ◽  
A.A. Schneiter ◽  
E.I. El Tayeb
Keyword(s):  
Seed Germination ◽  
Helianthus Annuus ◽  
Maximum Rate ◽  
Germination Rate ◽  
Thermal Time ◽  
Large Temperature ◽  
Climatic Zones ◽  
Helianthus Annuus L ◽  
Wide Range ◽  
Cardinal Temperature

SUMMARY Seed germination of six sunflower (Helianthus annuus L.) hybrids was investigated across a range of eleven constant temperatures between 5°C and 45°C. Large temperature differences in germination rate 1/t (d-1), cardinal temperature (°C) and thermal time θ (°cd) were observed among hybrids. Base temperatures (Tb) varied between 3.3°C and 6.7°C whereas maximum germination temperatures (Tm) varied between 41.7°C and 48.9°C. Final germination fraction was attained at 15°C - 25°C whereas the maximum rate of germination was attained at 30.4°C - 35.6°C. The maximum germination rate of hybrid USDA 894, the cultivar with the slowest germination rate, was only 50% of that of hybrid EX 47. The low Tb and high Tm of sunflower appear to be one of the factors which explain the successful adaptation of sunflower to a wide range of temperature. These findings are discussed in relation to the origin of the crop and its wide adaptations in diverse habitats and climatic zones.

scholarly journals Seed priming for increased seed germination and enhanced seedling vigor of winter rice

2021 ◽  
Vol 756 (1) ◽  
pp. 012047
Author(s):  
M P Anwar ◽  
R Jahan ◽  
M R Rahman ◽  
A K M M Islam ◽  
F M J Uddin
Keyword(s):  
Seed Germination ◽  
Seed Priming ◽  
Seedling Vigor

scholarly journals Variance prior specification for a basket trial design using Bayesian hierarchical modeling

2018 ◽  
Vol 16 (2) ◽  
pp. 142-153 ◽  
Author(s):  
Kristen M Cunanan ◽  
Alexia Iasonos ◽  
Ronglai Shen ◽  
Mithat Gönen
Keyword(s):  
Standard Deviation ◽  
Prior Distribution ◽  
Hierarchical Modeling ◽  
Bayesian Hierarchical Modeling ◽  
Bayesian Hierarchical ◽  
Inverse Gamma ◽  
Wide Range ◽  
Basket Trial ◽  
Basket Trials ◽  
Variance Parameter

Background: In the era of targeted therapies, clinical trials in oncology are rapidly evolving, wherein patients from multiple diseases are now enrolled and treated according to their genomic mutation(s). In such trials, known as basket trials, the different disease cohorts form the different baskets for inference. Several approaches have been proposed in the literature to efficiently use information from all baskets while simultaneously screening to find individual baskets where the drug works. Most proposed methods are developed in a Bayesian paradigm that requires specifying a prior distribution for a variance parameter, which controls the degree to which information is shared across baskets. Methods: A common approach used to capture the correlated binary endpoints across baskets is Bayesian hierarchical modeling. We evaluate a Bayesian adaptive design in the context of a non-randomized basket trial and investigate three popular prior specifications: an inverse-gamma prior on the basket-level variance, a uniform prior and half-t prior on the basket-level standard deviation. Results: From our simulation study, we can see that the inverse-gamma prior is highly sensitive to the input hyperparameters. When the prior mean value of the variance parameter is set to be near zero [Formula: see text], this can lead to unacceptably high false-positive rates [Formula: see text] in some scenarios. Thus, use of this prior requires a fully comprehensive sensitivity analysis before implementation. Alternatively, we see that a prior that places sufficient mass in the tail, such as the uniform or half-t prior, displays desirable and robust operating characteristics over a wide range of prior specifications, with the caveat that the upper bound of the uniform prior and the scale parameter of the half-t prior must be larger than 1. Conclusion: Based on the simulation results, we recommend that those involved in designing basket trials that implement hierarchical modeling avoid using a prior distribution that places a majority of the density mass near zero for the variance parameter. Priors with this property force the model to share information regardless of the true efficacy configuration of the baskets. Many commonly used inverse-gamma prior specifications have this undesirable property. We recommend to instead consider the more robust uniform prior or half-t prior on the standard deviation.

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