THE EFFECT OF SHORT-TERM TEMPERATURE STRESS ON THE GERMINATION OF DILL SEEDS

2021 ◽  
Vol 22 (4) ◽  
pp. 57-67
Author(s):  
A.F. Bukharov ◽  
◽  
D.N. Baleev ◽  
V.V. Vostrikov ◽  
N.A. Eremina ◽  
...  
Keyword(s):  
High Temperature ◽  
Seed Germination ◽  
Incubation Period ◽  
Germination Rate ◽  
Second Order ◽  
Short Term ◽  
Significance Level ◽  
Standard Temperature ◽  
First Order ◽  
Temperature Conditions

New data on the process of germination of dill seeds of the first and second orders after short-term heat stress (40 ° C) have been obtained. Seed germination was carried out in a thermostat. Swollen seeds (four repetitions of 100 seeds) were exposed to a temperature of 40 ° C in accordance with the scheme of the experiment: 0 (control); 1; 2; 3; 4 and 5 days. After incubation, the seeds were transferred to standard (t = 20 ° C) conditions and germinated in Petri dishes on filter paper with-out access to light for 21 days. Methods of analysis of seed germination in dynamics are used. Log-logistic regression with three parameters was used to construct the seed germination curve: b, d, e. All statistical analyses were performed in R version 3.4.3. The duration of the action of high temperature, which has an inhibitory effect on the germination rate and the number of germinated seeds, was revealed. Seeds of the first order in the control and after incubation for 1-3 days germi-nated in a similar way, and with an increase in the incubation period to 4-5 days, the rate of ger-mination decreased sharply. The seeds of the second order were even less resistant to the action of a short high-temperature stressor, and when the seeds were incubated for 3 days and then trans-ferred to standard temperature conditions, germination did not occur. The germination time of 50% of seeds (T50) of the first order as a result of a sequential increase in the incubation period at 40 ° C increased from 0.92 ± 0.11 to 6.4 ± 0.49 (p<0.001) days, respectively. Seeds of the second order during incubation for 1-2 days also germinated significantly slower compared to the control, and in the future germination did not occur. The curves of changes in the index of maximum seed germination, especially for the second order of branching, had a sharp bend when the critical dose of the temperature factor was exceeded. After that, there was a sharp decrease in the speed of seed germination up to a complete stop. The maximum incubation time (at 40 ° C), after which germi-nation is possible under standard temperature conditions, was 3.69 ± 0.06 days for the first order, and 2.00 ± 0.19 days for the second order. The difference was significant at the significance level of p<0.001.

The Effect of High Concentrations of Ethylene on Seed Germination of Douglas Fir (Pseudotsugamenziesii (Mirb.) Franco)

1975 ◽  
Vol 5 (3) ◽  
pp. 419-423 ◽  
Author(s):  
Carey Borno ◽  
Iain E. P. Taylor
Keyword(s):  
Seed Germination ◽  
Germination Rate ◽  
Inhibitory Effect ◽  
Germination Percentage ◽  
Douglas Fir ◽  
Control Treatment ◽  
Continuous Exposure ◽  
Short Term ◽  
Short Term Exposure ◽  
High Concentrations

Stratified, imbibed Douglas fir (Pseudotsugamenziesii (Mirb.) Franco) seeds were exposed to 100% ethylene for times between 0 and 366 h. Germination rate and germination percentage were increased by treatments up to 48 h. The 12-h treatment gave largest stimulation; 30% enhancement of final germination percentage over control. Treatment for 96 h caused increased germination rate for the first 5 days but reduced the germination percentage. Germinants were subject to continuous exposure to atmospheres containing 0.1 – 200 000 ppm ethylene in air, but it did not stimulate growth, and the gas was inhibitory above 100 ppm. Although some effects of high concentrations of ethylene may have been due to the lowering of oxygen supplies, this alone was insufficient to account for the full inhibitory effect. The mechanism of stimulation by short-term exposure to ethylene is discussed.

scholarly journals Seed germination of Chresta sphaerocephala DC. and Lessingianthus bardanoides (Less.) H. Rob. (asteraceae) from Cerrado

2010 ◽  
Vol 53 (6) ◽  
pp. 1299-1308 ◽  
Author(s):  
Graziela Cury ◽  
Ana Dionísia da Luz Coelho Novembre ◽  
Beatriz Appezzato da Glória
Keyword(s):  
Seed Germination ◽  
Germination Rate ◽  
Temperature Conditions ◽  
Number Of Seeds

This work aimed to study the effects of different temperature conditions on the germination of L. bardanoides and C. sphaerocephala seeds, compare the germination rates of these two species and estimate the occurrence of embryoless seeds. The results indicated that the best temperatures for the germination of L. bardanoides seeds were 20, 25 and 20-30ºC and for C. sphaerocephala, 20-35ºC and 40.32 µmol m-²s-¹ irradiance; L. bardanoides had a higher germination rate since the number of seeds with embryos higher compared with C. sphaerocephala.

Application of the Method of Second Order Sign Behavior To the Study of Non-Spatial Delayed Response in Rhesus Monkeys

Behaviour ◽  
1969 ◽  
Vol 35 (1-2) ◽  
pp. 128-136 ◽  
Author(s):  
Bruno Cardu
Keyword(s):  
Rhesus Monkeys ◽  
Short Term Memory ◽  
Memory Span ◽  
Second Order ◽  
Delayed Response ◽  
Short Term ◽  
Term Memory ◽  
First Order ◽  
The Moment ◽  
Sign Behavior

AbstractThe behavior of seven rhesus monkeys on a test of non-spatial delayed response based on the method of second order sign behavior is reported. Four stimuli were used: two first order stimuli presented individually (two sounds or two lights) and two second order stimuli presented simultaneously (two objects). Subjects first learned to associate one of the objects to each of the two first order stimuli. An interval between the termination of the first signal and the moment of choice was then introduced; hence the subjects' short-term memory could be estimated. All subjects succeeded in this task; the limits of the memory span ranged from 20 to 45 seconds.

scholarly journals Impacts of high temperature on embryonic growth and seed germination of dill (Anethum graveolens)

2021 ◽  
Author(s):  
Alexander F. Bukharov ◽  
Dmitry N. Baleev ◽  
Aleksey V. Soldatenko ◽  
Farhad B. Musaev ◽  
Parfait Kezimana ◽  
...  
Keyword(s):  
High Temperature ◽  
Seed Germination ◽  
Heat Exposure ◽  
Mother Plant ◽  
Anethum Graveolens ◽  
Short Term ◽  
Exogenous Factor ◽  
Seed Formation ◽  
Agricultural Plants ◽  
Growth Development

Temperature is the main exogenous factor that determines the growth, development and productivity of agricultural plants, including seed germination. In this work, we studied the thermosensitivity of heterogeneous dill seeds (Anethum graveolens). The study aimed to study the short-term (1-5 days) effect of high temperature (40&deg;C) on the growth of the embryo and germination of dill seeds formed on different umbels of the mother plant. The growth of the embryo had a significant effect on seed germination (r = 0.976; P &lt; 0.001). Seeds collected from primary umbels have a more developed embryo and can overcome the effects of thermal stress. We also found that the duration of heat exposure at 40&deg;C, leading to a decrease in viability, can vary from 1-5 days for seeds from primary umbels, to 1-2 days for seeds from secondary umbels, which, in our opinion, is due to the heteromorphism. The influence of the place of seed formation on the mother plant and the high temperature during germination is critical for embryo growth and dill seeds’ germination.

scholarly journals COVID-19 vaccination status should not be used in triage tie-breaking

2022 ◽  
pp. medethics-2021-107836
Author(s):  
Olivia Schuman ◽  
Joelle Robertson-Preidler ◽  
Trevor M Bibler
Keyword(s):  
Second Order ◽  
Vaccination Status ◽  
Short Term ◽  
Term Survival ◽  
First Order ◽  
Medical Institutions ◽  
The Usa ◽  
Predominant Strain ◽  
Triage Decisions ◽  
Short Term Survival

This article discusses the triage response to the COVID-19 delta variant surge of 2021. One issue that distinguishes the delta wave from earlier surges is that by the time it became the predominant strain in the USA in July 2021, safe and effective vaccines against COVID-19 had been available for all US adults for several months. We consider whether healthcare professionals and triage committees would have been justified in prioritising patients with COVID-19 who are vaccinated above those who are unvaccinated in first-order or second-order triage. Given that lack of evidence for a correlation between short-term survival and vaccination, we argue that using vaccination status during first-order triage would be inconsistent with accepted triage standards. We then turn to notions of procedural fairness, equity and desert to argue that that there is also a lack of justification for using vaccination status in second-order triage. In planning for future surges, we recommend that medical institutions base their triage decisions on principles meant to save the most lives, minimise inequity and protect the public’s trust, which for the time being would not be served by the inclusion of vaccination status.

scholarly journals Seed Enhancements to Improve Spinach Germination

HortScience ◽  
2001 ◽  
Vol 36 (5) ◽  
pp. 979-981 ◽  
Author(s):  
Leslie S. Katzman ◽  
Alan G. Taylor ◽  
Robert W. Langhans
Keyword(s):  
High Temperature ◽  
Seed Germination ◽  
Spinacia Oleracea ◽  
Germination Rate ◽  
Component Analysis ◽  
Seed Treatments ◽  
Germination Time ◽  
High Uniformity ◽  
Germination Temperature ◽  
Improve Seed Germination

Rapid, synchronized, and high percentage of germination is required for commercial spinach (Spinacia oleracea L.) production using hydroponic techniques. Seed treatments examined to improve seed germination were: 1) decoating; 2) leaching in water; and 3) soaking seeds for 4 hours in 0.5% NaOCl, leaching for 15 hours in water, and sowing in 0.3% H2O2 (this treatment will be referred to as NaOCl/H2O2). Germination studies were conducted on four cultivars at a constant 18 °C (optimal) or 30 °C (inhibitory). At 18 °C, germination rate (T50) was maximized by both hydration treatments, but uniformity of germination (Tsd) was greatest for decoated seeds; final germination was ≥89% for all treatments. At 30 °C, decoating resulted in greatest uniformity of germination. The NaOCl/H2O2 treatment resulted in highest germination (94%) at the high temperature, whereas decoating was least effective (69%). Reduced germination of decoated seeds was attributed to atypical germinants. Cultivars differed in response to the treatments at both temperatures. Component analysis of the NaOCl/H2O2 treatment was studied with two slow-to-germinate cultivars. Treatment with H2O2, with or without NaOCl, improved the rate, uniformity, and percentage of germination of seeds of both cultivars, but NaOCl alone did not. Pericarp removal or pericarp removal plus NaOCl/H2O2 treatments reduced variability in germination time and enhanced speed of germination at 30 °C, but decoating produced a higher percentage of atypical seedlings than did other treatments. Therefore, the NaOCl/H2O2 treatment is recommended for growers who are unable to maintain cool germination temperatures and/or cannot afford the costs associated with cooling. If growers can maintain a germination temperature of ≈18 °C, decoated seeds are preferable, based on the high uniformity of germination.

Effect of heat stress during seed development and maturation on wheat (Triticum durum) seed quality. I. Seed germination and seedling vigor

1995 ◽  
Vol 75 (4) ◽  
pp. 821-829 ◽  
Author(s):  
L. Grass ◽  
J. S. Burris
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Seed Germination ◽  
Oxygen Uptake ◽  
Seed Development ◽  
Seed Quality ◽  
Seed Vigor ◽  
Growth Potential ◽  
Cool Temperature ◽  
Temperature Conditions

Two wheat cultivars, Marzak and Oum-rabia, were subjected to three temperature regimes (20/15, 28/21, 36/29 °C) beginning 10 d after anthesis to maturity. As expected, high temperature resulted in low values of both seed yield and physical traits of seed quality. The effect of temperature on seed germination was not consistent among the two cultivars. High temperature during seed development and maturity had no effect on seed germination of Oum-rabia, whereas it decreased seed germination of Marzak. In contrast to seed germination, seed vigor was adversely affected by heat stress. This decline in seed vigor was reflected in reduced shoot and root dry weight, increased shoot/root ratio, reduced root length, low root number per seedling, and high seed conductivity. Excised embryo culture showed marked differences in the embryo growth potential. Although embryos from all treatments had germinated, a delay of 24–48 h was observed in the germination of embryos excised from seeds grown under high temperature conditions. Also, their shoot and radicle development over time lagged behind that of embryos isolated from seeds grown under cool temperature conditions. Exposing seeds to high temperature during development and maturity also resulted in low embryo oxygen uptake. Results presented in this study show that the growing conditions, in this instance temperature, of the parent plant affect the quality of its seed. Key words: Embryo, germination, oxygen uptake, vigor, wheat, high temperature

Sign in / Sign up

Export Citation Format

Share Document