Thermal regulation of secondary dormancy induction inPolygonum aviculareseeds: a quantitative analysis using the hydrotime model

2017 ◽  
Vol 27 (3) ◽  
pp. 231-242 ◽  
Author(s):  
Diego Batlla ◽  
Andrés Mateo Agostinelli
Keyword(s):  
Storage Temperature ◽  
Effect Of Temperature ◽  
Model Parameters ◽  
Polygonum Aviculare ◽  
Secondary Dormancy ◽  
Different Temperatures ◽  
Germination Behaviour ◽  
Model Equations ◽  
Hydrotime Model ◽  
Dormancy Induction

AbstractFor seed banks showing seasonal changes in their dormancy level, the possibility of predicting temporal patterns of emergence depends on establishing a robust relationship between temperature and the rate of dormancy loss and induction. However, although the effect of temperature on dormancy loss has been extensively studied, less work has been advocated to the quantification of temperature effects on dormancy induction. In the present work, we quantified temperature regulation of dormancy induction inPolygonum aviculareseeds using the hydrotime model. To study induction into secondary dormancy, seeds previously released from primary dormancy through stratification at 5°C were stored at dormancy-inductive temperatures of 10, 15, 20 and 25°C for different periods. During storage, seeds were germinated at different temperatures and water potentials, and hydrotime model parameters were derived. Changes in hydrotime model parameters (mean base water potential for germination and its standard deviation, and the hydrotime required for germination) during dormancy induction were described by adjusting exponential equations. Obtained results indicated a minimum temperature for dormancy induction of 8.7°C and the existence of a bi-linear relationship between rate of induction into secondary dormancy and storage temperature, in which storage temperatures around 25°C showed a higher dormancy induction rate than those below 20°C. Developed model equations were then used to predict changes in germination behaviour during dormancy induction at different temperatures, showing a good agreement between simulated and observed values.

scholarly journals Secondary dormancy induction and release inBromus tectorumseeds: the role of temperature, water potential and hydrothermal time

2017 ◽  
Vol 27 (1) ◽  
pp. 12-25 ◽  
Author(s):  
K. K. Hawkins ◽  
P.S. Allen ◽  
S.E. Meyer
Keyword(s):  
Water Potential ◽  
Model Parameters ◽  
Hydrothermal Time ◽  
Primary Dormancy ◽  
Secondary Dormancy ◽  
Short Period ◽  
Dry Conditions ◽  
Time Parameters ◽  
Germination Timing ◽  
Dormancy Induction

AbstractSeeds of the winter annualBromus tectorumlose primary dormancy in summer and are poised to germinate rapidly in the autumn. If rainfall is inadequate, seeds remain ungerminated and may enter secondary dormancy under winter conditions. We quantified conditions under which seeds enter secondary dormancy in the laboratory and field and also examined whether contrastingB. tectorumgenotypes responded differently to dormancy induction cues. The study also extends previous hydrothermal time models for primary dormancy loss and germination timing inB. tectorumby using similar models to account for induction and loss of secondary dormancy. Maximum secondary dormancy was achieved in the laboratory after 4 weeks at –1.0 MPa and 5°C. Seeds in the field became increasingly dormant through exposure to temperatures and water potentials in this range, confirming laboratory results. They were released from dormancy through secondary after-ripening the following summer. Different genotypes showed contrasting responses to dormancy induction cues in both laboratory and field. To examine secondary dormancy induction and release in the field in terms of hydrothermal time parameters, we first created a model that allowed mean base water potential (Ψb(50)) to vary while holding other hydrothermal time parameters constant, as in models for primary dormancy loss under dry conditions. The second model allowed all three model parameters to vary through time, to account for changes (e.g. hydrothermal time accumulation) that could occur simultaneously with dormancy induction in imbibed seeds. Shifts in Ψb(50) could explain most changes in dormancy status for seeds retrieved from the field, except during the short period prior to dormancy induction, when hydrothermal time was accumulating. This study illustrates that hydrothermal modelling, and specifically changes in Ψb(50), can be used to characterize secondary dormancy induction and loss inB. tectorum.

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

2011 ◽  
Vol 78 (2) ◽  
pp. 105-114 ◽  
Author(s):  
Anna Bochenek ◽  
Janusz Gołaszewski ◽  
Agnieszka I. Piotrowicz-Cieślak ◽  
Ryszard J. Górecki
Keyword(s):  
Water Stress ◽  
Seed Dormancy ◽  
Cirsium Arvense ◽  
Model Parameters ◽  
Physiological Basis ◽  
Water Stress Tolerance ◽  
Different Temperatures ◽  
Average Water ◽  
Hydrotime Model ◽  
Fluctuating Temperatures

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

Secondary dormancy dynamics depends on primary dormancy status inArabidopsis thaliana

2015 ◽  
Vol 25 (2) ◽  
pp. 230-246 ◽  
Author(s):  
Gabriela A. Auge ◽  
Logan K. Blair ◽  
Liana T. Burghardt ◽  
Jennifer Coughlan ◽  
Brianne Edwards ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Seedling Survival ◽  
Seed Maturation ◽  
Maternal Plant ◽  
Primary Dormancy ◽  
Secondary Dormancy ◽  
Different Temperatures ◽  
Time Of Year ◽  
Dormancy Induction ◽  
Different Levels

AbstractSeed dormancy can prevent germination under unfavourable conditions that reduce the chances of seedling survival. Freshly harvested seeds often have strong primary dormancy that depends on the temperature experienced by the maternal plant and which is gradually released through afterripening. However, seeds can be induced into secondary dormancy if they experience conditions or cues of future unfavourable conditions. Whether this secondary dormancy induction is influenced by seed-maturation conditions and primary dormancy has not been explored in depth. In this study, we examined secondary dormancy induction in seeds ofArabidopsis thalianamatured under different temperatures and with different levels of afterripening. We found that low water potential and a range of temperatures, from 8°C to 35°C, induced secondary dormancy. Secondary dormancy induction was affected by the state of primary dormancy of the seeds. Specifically, afterripening had a non-monotonic effect on the ability to be induced into secondary dormancy by stratification; first increasing in sensitivity as afterripening proceeded, then declining in sensitivity after 5 months of afterripening, finally increasing again by 18 months of afterripening. Seed-maturation temperature sometimes had effects that were independent of expressed primary dormancy, such that seeds that had matured at low temperature, but which had comparable germination proportions as seeds matured at warmer temperatures, were more easily induced into secondary dormancy. Because seed-maturation temperature is a cue of when seeds were matured and dispersed, these results suggest that the interaction of seed-maturation temperature, afterripening and post-dispersal conditions all combine to regulate the time of year of seed germination.

Storage of whole blood: effect of temperature on the measured concentration of analytes in serum.

1988 ◽  
Vol 34 (10) ◽  
pp. 2111-2114 ◽  
Author(s):  
N N Rehak ◽  
B T Chiang
Keyword(s):  
Whole Blood ◽  
Storage Temperature ◽  
Inorganic Phosphorus ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Measured Concentration ◽  
Fresh Serum ◽  
Prolonged Contact ◽  
Different Temperatures

Abstract We measured the concentrations of 29 commonly measured analytes in fresh sera and in sera that had been stored as whole blood at seven different temperatures for 24 h. We determined the effect of storage temperature and prolonged contact with cell clot on the measured concentration of each analyte, with fresh serum as the control. Significant differences were observed for concentrations of creatinine, glucose, inorganic phosphorus, potassium, and both aminotransferases. The extent of these differences was temperature dependent. Values for the remaining 23 analytes examined were essentially unaffected by the storage.

Modeling the effect of temperature on survival rate of Salmonella Enteritidis in yogurt

2014 ◽  
Vol 17 (3) ◽  
pp. 479-485 ◽  
Author(s):  
J. Szczawiński ◽  
M. E. Szczawińska ◽  
A. Łobacz ◽  
A. Jackowska-Tracz
Keyword(s):  
Survival Rate ◽  
Salmonella Enteritidis ◽  
Storage Time ◽  
Storage Temperature ◽  
Effect Of Temperature ◽  
Polynomial Equations ◽  
Natural Logarithm ◽  
Primary Model ◽  
Different Temperatures ◽  
Number Of Bacteria

Abstract The aim of the study was to determine the inactivation rates of Salmonella Enteritidis in commercially produced yogurt and to generate primary and secondary mathematical models to predict the behaviour of these bacteria during storage at different temperatures. The samples were inoculated with the mixture of three S. Enteritidis strains and stored at 5oC, 10oC, 15oC, 20oC and 25oC for 24 h. The number of salmonellae was determined every two hours. It was found that the number of bacteria decreased linearly with storage time in all samples. Storage temperature and pH of yogurt significantly influenced survival rate of S. Enteritidis (p < 0.05). In samples kept at 5oC the number of salmonellae decreased at the lowest rate, whereas at 25°C the reduction in number of bacteria was the most dynamic. The natural logarithm of mean inactivation rates of Salmonella calculated from primary model was fitted to two secondary models: linear and polynomial. Equations obtained from both secondary models can be applied as a tool for prediction of inactivation rate of Salmonella in yogurt stored under temperature range from 5 to 25°C; however, polynomial model gave the better fit to the experimental data.

scholarly journals Ecological characterisation of the Colombian entomopathogenic nematode Heterorhabditis sp. SL0708

2013 ◽  
Vol 73 (2) ◽  
pp. 239-243 ◽  
Author(s):  
MC Mejia-Torres ◽  
A Sáenz
Keyword(s):  
Galleria Mellonella ◽  
Storage Temperature ◽  
Entomopathogenic Nematode ◽  
Effect Of Temperature ◽  
Different Temperatures ◽  
Valle Del Cauca ◽  
And Storage

The entomopathogenic nematode Heterorhabditis sp. SL0708 (Rhabditida: Heterorhabditidae) isolated from soil in Alcalá, Valle del Cauca (Colombia) was characterised ecologically using Galleria mellonella larvae (L) (Pyralidae: Galleriinae) as hosts. The effect of temperature on the viability, infectivity and reproduction, and of moisture on infectivity and storage in liquid were evaluated in infective juveniles (IJs). Significant differences were found in the viability, infectivity and reproduction of the IJs at different temperatures. No nematodes were recovered at 5 °C and 10 °C, and at 35 °C no infectivity was observed. Average daily nematode recovery was best at 25 °C, and survival of the IJs was low in substrates presenting 13% moisture. The optimal storage temperature for Heterorhabditis sp. SL0708 was between 20 °C and 30 °C, keeping its infectivity for up to 8 weeks.

scholarly journals Modelling the effect of temperature on the probabilistic stress–life fatigue diagram of glass fibre–polymer composites loaded in tension along the fibre direction

2017 ◽  
Vol 52 (2) ◽  
pp. 207-224 ◽  
Author(s):  
Laurent Cormier ◽  
Simon Joncas
Keyword(s):  
Fatigue Life ◽  
Temperature Dependence ◽  
Polymer Composites ◽  
Static Strength ◽  
Fatigue Performance ◽  
Effect Of Temperature ◽  
Model Parameters ◽  
Fibre Direction ◽  
Single Temperature ◽  
Different Temperatures

Predicting the fatigue performance of composites has proven to be a challenge both conceptually, due to the inherent complexity of the phenomenon, and practically, because of the resource-intensive process of fatigue testing. Moreover, mechanical behaviour of polymer matrix composites exhibits a complicated temperature dependence, making the prediction of fatigue performance under different temperatures even more complex and resource intensive. The objective of this paper is to provide a method for the prediction of fatigue life of glass–polymer composites loaded in the fibre direction at various temperatures with minimal experimental efforts. This is achieved by using a static strength degradation approach to fatigue modelling, where only two parameters (including static strength) are temperature dependent, in conjunction with relationships for these two fatigue model parameters temperature dependence. The method relies on fatigue data at a single temperature and simple static tests at different temperatures to predict the effects of temperature on the material’s fatigue behaviour. The model is validated on experimental data for two unidirectional and one woven glass–epoxy composites and is found to accurately predict the effect of temperature on fatigue life of composites. A method to obtain probabilistic stress-life [Formula: see text] fatigue diagrams including temperature effects is also presented.

scholarly journals Effect of Temperature on the Expression of Classical Enterotoxin Genes among Staphylococci Associated with Bovine Mastitis

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 975
Author(s):  
Theeyathart Homsombat ◽  
Sukolrat Boonyayatra ◽  
Nattakarn Awaiwanont ◽  
Duangporn Pichpol
Keyword(s):  
Room Temperature ◽  
Storage Temperature ◽  
Bovine Mastitis ◽  
Food Poisoning ◽  
Staphylococcal Enterotoxin ◽  
Effect Of Temperature ◽  
Coagulase Negative Staphylococci ◽  
Enterotoxin Genes ◽  
Different Temperatures ◽  
High Temperature Processing

Staphylococcal food poisoning (SFP), caused by the contamination of staphylococcal enterotoxins, is a common foodborne disease worldwide. The aims of this study were: (1) to investigate classical staphylococcal enterotoxin genes, sea, seb, sec, sed, and see, among Staphylococcus aureus and coagulase-negative staphylococci (CNS) associated with bovine mastitis; (2) to determine the effect of temperature on the expression of classical staphylococcal enterotoxin genes in staphylococci in milk. The detection of classical staphylococcal enterotoxin genes was performed using S. aureus (n = 51) and CNS (n = 47). The expression of classical enterotoxin genes, including sea, seb, sec, and see, was determined during the growth of staphylococci in milk subjected to ultra-high-temperature processing at two different temperatures: 8 °C and room temperature. Classical staphylococcal enterotoxin genes were expressed more frequently in S. aureus (35.30%) than in CNS (12.77%). The sec gene was most frequently detected in S. aureus (29.41%) and CNS (6.38%). Moreover, the expression of sea and sec was significantly higher at room temperature than at 8 °C after 16 h of incubation (p < 0.05). These results emphasize the importance of maintaining the storage temperature of milk below 8 °C to reduce the risk of SFP.

scholarly journals The Respiration of some Planktonic copepods II. The Effect Of Temperature

1953 ◽  
Vol 31 (3) ◽  
pp. 447-460 ◽  
Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont
Keyword(s):  
Respiratory Rate ◽  
The Body ◽  
The Other ◽  
Effect Of Temperature ◽  
Acartia Clausi ◽  
Temora Longicornis ◽  
Different Temperatures ◽  
Planktonic Copepods ◽  
The Difference ◽  
The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

scholarly journals Effect of temperature, CO2 and O2 on motility and mobility of Anisakidae larvae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël
Keyword(s):  
Enzymatic Digestion ◽  
Infected Fish ◽  
Effect Of Temperature ◽  
Video Recordings ◽  
Different Temperatures ◽  
Semi Solid ◽  
Zoonotic Parasites ◽  
The Impact ◽  
Phosphate Buffered Saline

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.

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