Germination of leafy spurge (Euphorbia esula L.) seeds under alternating temperatures: the effects of amplitude, midpoint, and imbibition in gibberellic acid

2016 ◽  
Vol 96 (3) ◽  
pp. 321-328
Author(s):  
Michael E. Foley
Keyword(s):  
Gibberellic Acid ◽  
Constant Temperature ◽  
Temperature Regime ◽  
Initial Temperature ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Amplitude Difference ◽  
Temperature Regimes ◽  
Alternating Temperature

Germinability of dormant seeds or the capacity to germinate under particular conditions is sometimes enhanced by a diurnal alternating temperature regime relative to a constant temperature. Alternating temperature regimes vary in amplitude (difference between the minimum and maximum) and midpoint (average). The aim of this research was to test the effects of amplitude and midpoint regimes on germination of dormant leafy spurge seed from a Fargo, ND population in water and gibberellic acid (GA3). The optimal regimes for germination in both water and GA3 were 20:30 °C (16 h:8 h) and 20:35 °C (19 h:5 h), which provided amplitudes of 10 °C and 15 °C, respectively, with both conditions having a midpoint temperature of 23.3 °C. However, midpoint temperature of 22 °C to 27 °C were equally effective for germination under the 20:30 °C and 20:35 °C alternating temperature regimes. Additional alternating temperature regimes with amplitudes of 15 °C (15:30 °C and 10:25 °C), 20 °C (10:30 °C), and 25 °C (10:35 °C) generally displayed reduced germination in both water and GA3, which is likely attributable to the low initial alternating temperature (≤15 °C) component of the regime relative to the higher initial temperature of 20 °C for the optimum regimes of 20:30 °C and 20:35 °C. Under the alternating temperature regimes tested, seeds germinated in GA3 generally displayed higher germination (≥80%) compared with seeds in water (30%–50%).

Can alternating temperature, moist chilling, and gibberellin interchangeably promote the completion of germination in Clematis vitalba seeds?

Botany ◽  
2017 ◽  
Vol 95 (8) ◽  
pp. 847-852 ◽  
Author(s):  
Rosangela Picciau ◽  
Marco Porceddu ◽  
Gianluigi Bacchetta
Keyword(s):  
Seed Germination ◽  
Gibberellic Acid ◽  
Plant Species ◽  
Temperature Regime ◽  
Fluctuating Temperature ◽  
Temperature Regimes ◽  
Moist Chilling ◽  
Clematis Vitalba ◽  
Alternating Temperature ◽  
Positive Effect

Each plant species has particular requirements for seed germination, and some of them respond differently to constant or alternating temperature regimes. In this study, the interchangeable effects of different treatments and temperatures on the completion of seed germination of Clematis vitalba L. were investigated. The seeds were tested with a constant (from 5 °C to 25 °C) or a fluctuating (25/10 °C) temperature regime, and the effect of gibberellic acid (GA3), incubation at warm (W) or cold (C) temperatures while being imbibed, and drying after ripening (DAR) were evaluated. The final germination percentages and the time in days required to reach 50% of germination (T50) were calculated. GA3 and C significantly enhanced completion of seed germination at all of the temperatures tested. A strong positive effect of alternating temperature was observed, which triggered completion of seed germination regardless of treatment. Under the fluctuating temperature, the chilled seeds had the most rapid germination. Low germination rates were observed for both control and DAR treatments. Seeds of C. vitalba display a certain degree of dormancy, which can be broken by moist chilling and GA3 treatments. Moreover, alternating temperature stimulates the completion of seed germination by satisfying certain physiological requirements for germination under constant temperatures.

scholarly journals Assessing the role of two populations of Aedes japonicus japonicus for Zika virus transmission under a constant and a fluctuating temperature regime

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Uros Glavinic ◽  
Jasmin Varga ◽  
Anca Ioana Paslaru ◽  
Jeannine Hauri ◽  
Paul Torgerson ◽  
...  
Keyword(s):  
Constant Temperature ◽  
Temperature Regime ◽  
Zika Virus ◽  
Incubation Temperature ◽  
Transmission Rate ◽  
Control Measures ◽  
Fluctuating Temperature ◽  
Laboratory Conditions ◽  
Temperature Regimes ◽  
Two Populations

Abstract Background Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other flaviviruses (e.g. West Nile, dengue and yellow fever), have been described as potential vectors for ZIKV under laboratory conditions. One of these, the Asian bush mosquito, Ae. japonicus, is widely distributed with high abundances in central-western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14–27 °C, mean 23 °C) temperature regimes. Results The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post-exposure to infectious rabbit blood. The highest amount of plaque forming units (PFU) (400/ml) were recorded 14 days post-oral infection in the Swiss population incubated at a constant temperature. No difference in terms of infection, dissemination and transmission rate were found between mosquito populations. Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates compared to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7–23% and 7–10% for the constant temperature and 0–10% and 3–27% under fluctuating temperatures for the Swiss and the French populations, respectively. Conclusions To the best of our knowledge, this is the first study confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics.

Germination of Seeds of Perennial Pepperweed (Lepidium latifolium)

Weed Science ◽  
1986 ◽  
Vol 34 (2) ◽  
pp. 252-255 ◽  
Author(s):  
Gerald K. Miller ◽  
James A. Young ◽  
Raymond A. Evans
Keyword(s):  
United States ◽  
Constant Temperature ◽  
Western United States ◽  
Lepidium Latifolium ◽  
Temperature Regimes ◽  
Riparian Habitats ◽  
Alternating Temperature

Perennial pepperweed (Lepidium latifoliumL. # LEPLA) is a serious weed of meadows and riparian habitats in the intermountain area of the western United States. Germination of seeds of this species was tested at 55 constant- and alternating-temperature regimes. No significant differences were found in mean germination at a range of temperatures varying from 0 to 40 C for seedlots collected at the same site in different years or at different locations in the same year. Optimum germination not significantly (P = 0.01) lower than the maximum observed occurred most frequently at 5/40 C (5 C for 16 h and 40 C for 8 h), and 10/40 and 15/40 C. Germination was enhanced by alternating regimes with low night temperatures (0, 2, or 5 C) and high day temperatures (35 and 40 C), in comparison with more moderate constant-temperature regimes.

Changes in the Transcriptome of Dry Leafy Spurge (Euphorbia esula) Seeds Imbibed at a Constant and Alternating Temperature

Weed Science ◽  
2012 ◽  
Vol 60 (1) ◽  
pp. 48-56 ◽  
Author(s):  
Michael E. Foley ◽  
Wun S. Chao ◽  
Münevver Doğramaci ◽  
David P. Horvath ◽  
James V. Anderson
Keyword(s):  
Stress Responses ◽  
Anaerobic Respiration ◽  
Reducing Power ◽  
Principal Component ◽  
Leafy Spurge ◽  
Specific Effects ◽  
Temperature Regimes ◽  
Stress Related Genes ◽  
Alternating Temperature ◽  
Species Specific

Leafy spurge seeds are responsive to alternating temperature rather than constant temperature for germination. Transcriptome changes of dry leafy spurge seeds and seeds imbibed for 1 and 3 d at 20 C constant (C) and 20 : 30 C alternating (A) temperature were determined by microarray analysis to examine temperature responsiveness. Principal component analysis revealed differences in the transcriptome of imbibed seeds based on the temperature regime. Computational methods in bioinformatics parsed the data into overrepresented AraCyc pathways and gene regulation subnetworks providing biological context to temperature responses. After 1 d of imbibition, the degradation of starch and sucrose leading to anaerobic respiration were common pathways at both temperature regimes. Several overrepresented pathways unique to 1 d A were associated with generation of energy, reducing power, and carbon substrates; several of these pathways remained overrepresented and up-regulated at 3 d A. At 1 d C, pathways for the phytohormones jasmonic acid and brassinosteroids were uniquely overrepresented. There was little similarity in overrepresented pathways at 1 d C between leafy spurge and arabidopsis seeds, indicating species-specific effects upon imbibition of dry seeds. Overrepresented gene subnetworks at 1 d and 3 d at both temperature regimes related to signaling processes and stress responses. A major overrepresented subnetwork unique to 1 d C related to photomorphogenesis via the E3 ubiquitin ligase COP1. At 1 d A, major overrepresented subnetworks involved circadian rhythm via LHY and TOC1 proteins and expression of stress-related genes such as DREB1A, which is subject to circadian regulation. Collectively, substantial differences were observed in the transcriptome of leafy spurge seeds imbibed under conditions that affect the capacity to germinate.

scholarly journals Assessing the role of two populations of Aedes japonicus japonicus for Zika virus transmission under a constant and a fluctuating temperature regime.

2020 ◽  
Author(s):  
Uros Glavinic ◽  
Jasmin Varga ◽  
Anca Iona Paslaru ◽  
Jeannine Hauri ◽  
Paul Torgerson ◽  
...  
Keyword(s):  
Constant Temperature ◽  
Temperature Regime ◽  
Zika Virus ◽  
Incubation Temperature ◽  
Transmission Rate ◽  
Control Measures ◽  
Fluctuating Temperature ◽  
Laboratory Conditions ◽  
Temperature Regimes ◽  
Two Populations

Abstract Background Since the huge epidemic of Zika virus (ZIKV) in Brazil in 2015, questions were raised to understand which mosquito species could transmit the virus. Aedes aegypti has been described as the main vector. However, other Aedes species (e.g. Ae. albopictus and Ae. japonicus) proven to be competent for other Flaviviruses (e.g.West Nile, dengue and yellow fever), have been described as potential vector for ZIKV under laboratory conditions. To name one, the Asian bush mosquito Ae. japonicus which is widely distributed with high abundances in Central-Western Europe. In the present study, infection, dissemination and transmission rates of ZIKV (Dak84 strain) in two populations of Ae. japonicus from Switzerland (Zürich) and France (Steinbach, Haut-Rhin) were investigated under constant (27 °C) and fluctuating (14-27 °C, mean 23 °C) temperature regimes.Results The two populations were each able to transmit ZIKV under both temperature regimes. Infectious virus particles were detected in the saliva of females from both populations, regardless of the incubation temperature regime, from 7 days post exposure to infectious rabbit blood. The highest amount of Plaque Forming Unit (PFU) (400/ml) were recorded 14 days post oral infection in the Swiss population incubated at constant temperature. No difference in term of infection, dissemination and transmission rate were found between mosquito populations.Temperature had no effect on infection rate but the fluctuating temperature regime resulted in higher dissemination rates comparing to constant temperature, regardless of the population. Finally, transmission efficiency ranged between 7-23% and 7-10% for the constant temperature and 0-10% and 3-27% under fluctuating temperatures for the Swiss and the French populations, respectively.Conclusions This is the first work confirming vector competence for ZIKV of Ae. japonicus originating from Switzerland and France at realistic summer temperatures under laboratory conditions. Considering the continuous spread of this species in the northern part of Europe and its adaptation at cooler temperatures, preventative control measures should be adopted to prevent possible ZIKV epidemics.

THE RESPONSE OF TWO STRAINS OF HYLEMYA ANTIQUA (DIPTERA: ANTHOMYIIDAE) TO A CONSTANT AND AN ALTERNATING TEMPERATURE REGIME

1979 ◽  
Vol 111 (11) ◽  
pp. 1207-1217 ◽  
Author(s):  
Alan S. Robinson ◽  
G. Zurlini
Keyword(s):  
Constant Temperature ◽  
Temperature Regime ◽  
Wild Strain ◽  
Laboratory Strain ◽  
Intrinsic Rate Of Increase ◽  
Net Reproductive Rate ◽  
Hylemya Antiqua ◽  
Rate Of Increase ◽  
Weighted Mean Temperature ◽  
Alternating Temperature

AbstractThe effect of an alternating and a constant temperature regime on some aspects of the biology of two strains of Hylemya antiqua were studied. One strain was a laboratory strain, the other a newly colonized wild strain. Several population statistics were assessed and life tables constructed. Significant differences between the strains were recorded.The laboratory strain mated significantly better under both environments than the wild strain, it also oviposited earlier and lived longer. No difference between the strains was recorded for either total egg production or oviposition rate. The wild strain larvae survived significantly better than the laboratory strain larvae and produced larger pupae. As the weighted mean temperature of the alternating regime was 16.6°C compared with the constant regime of 23°C many temperature dependent processes were retarded. Nevertheless as the alternating temperature increased larval survival and increased pupal size, this temperature regime has now been adopted for the routine laboratory rearing of H. antiqua larvae. The net reproductive rate, R0, and the intrinsic rate of increase, r, were calculated for both strains in both environments. The wild flies had the highest R0 at the alternating temperature and the lowest at the constant temperature. This trend was completely reversed when r was calculated as this statistic takes into account generation time, which was much shorter in the constant temperature.The results were discussed in the framework of the quality of the laboratory stock in relation to its use in a genetic control programme.

Germination characteristics of Artemisia ordosica (Asteraceae) in relation to ecological restoration in northern China

2005 ◽  
Vol 83 (8) ◽  
pp. 1021-1028 ◽  
Author(s):  
Yuanrun Zheng ◽  
Glyn M Rimmington ◽  
Yong Gao ◽  
Lianhe Jiang ◽  
Xuerong Xing ◽  
...  
Keyword(s):  
Temperature Regime ◽  
Northern China ◽  
Photon Flux ◽  
Artemisia Ordosica ◽  
Ordos Plateau ◽  
Temperature Regimes ◽  
Percent Germination ◽  
Alternating Temperature ◽  
Moisture Conditions ◽  
Semi Arid

Artemisia ordosica Krasch. (Asteraceae) is the dominant psammophytic shrub species on the Ordos Plateau of northern China and is used for revegetation of semi-arid areas. Experiments were conducted to determine the effects of light intensity, constant temperature, alternating temperatures, and water potential on germination to determine why air-dispersed achenes fail to germinate well in the field. Achenes germinated within a wide alternating temperature window, except under the 5:15 °C (night:day) temperature regime in darkness. Final percent germination (FPG) was higher in darkness than in light at alternating temperature regimes, except under the 20:30 °C (night:day) temperature regime. Achenes subjected to a range of constant temperatures in the dark had high FPG over 76.8% except at 30 °C (8%). Photosynthetic photon flux densities (PPFD) of 100 and 400 µmol·m–2·s–1 significantly lowered FPG under a 10:20 °C (night:day) regime, while at 0–25 µmol·m–2·s–1 PPFD, the FPG was over 92%. Few achenes germinated at –1.4 MPa. The most suitable temperature for germination of achenes placed under water stress was 20 °C. The best timing for air dispersal is mid-May, so seeds would become covered with sand at a time when temperature and soil moisture conditions were optimal for germination.Key words: air dispersal, Artemisia ordosica, hydrothermal time, psammophytes, semi-arid regions, temperature.

Growth Regulators and Chemicals Stimulate Germination of Leafy Spurge (Euphorbia esula) Seeds

Weed Science ◽  
2008 ◽  
Vol 56 (4) ◽  
pp. 516-522 ◽  
Author(s):  
Michael E. Foley ◽  
Wun S. Chao
Keyword(s):  
Growth Regulators ◽  
Potassium Phosphate ◽  
Fold Increase ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Naphthaleneacetic Acid ◽  
Citrate Buffer ◽  
Baseline Information ◽  
Alternating Temperature ◽  
Effective Growth

Baseline information on inducing germination of dormant leafy spurge seeds with growth regulators and chemicals is lacking. This study was conducted to survey the effect of various substances on germination of leafy spurge seeds. The nontreated control seeds in this population were nearly fully imbibed in 3 h and displayed approximately 35% germination in 21 d under the normal alternating temperature of 20/30 C (16/8 h). Gibberellic acid (GA3, 10 mM) induced 65% germination at constant temperatures of 20 and 30 C. The alternating temperature increased the effectiveness of 10 mM GA3with 94% germination, a twofold increase over the control. Nontreated seeds did not germinate at the constant temperatures, suggesting that alternating temperature acts via a GA-independent pathway. Kinetin at 0.1 to 1 mM was no more effective than the control, but a saturated solution of kinetin induced 73% germination. Ethephon at 0.01 to 1 mM induced 58 to 66% germination, although there was little response to different concentrations. Ethylene gas at 1 ppm stimulated germination to 77%, a 1.8-fold increase over the control. Germination of seeds incubated continuously in 1 and 10 mM nitrate displayed 35 and 40% germination, respectively. Seeds pulsed for 24 h with 100 mM nitrate displayed 58% germination after 21 d. Potassium phosphate–citrate buffer (pH 3.4) and its individual components induced 60 to 70% germination. Fluridone (10 and 100 µM), 1-naphthaleneacetic acid (NAA, 0.1 to 10 mM), and ethanol (0.2 to 15%) had no effect on germination, but subsequent elongation in the presence of NAA was inhibited because of swelling of the radicle. This research reveals that GA3is the most effective growth regulator for germination of dormant leafy spurge seeds, and its effect is independent of temperature.

Fall condition factor and temperature influence the incidence of metamorphosis in sea lampreys, Petromyzon marinus

1994 ◽  
Vol 72 (6) ◽  
pp. 1134-1140 ◽  
Author(s):  
John A. Holmes ◽  
John H. Youson
Keyword(s):  
Ambient Temperature ◽  
Constant Temperature ◽  
Temperature Regime ◽  
Condition Factor ◽  
Petromyzon Marinus ◽  
Population Differences ◽  
Temperature Influence ◽  
Temperature Regimes ◽  
Sea Lampreys ◽  
Effects Of Temperature

Larval sea lampreys of immediate premetamorphic size (at least 120 mm and 3.0 g) were subjected to ambient or constant 21 °C temperature regimes for 9 months to investigate the influence of temperature and a fall condition factor (CF) of 1.50 or greater on the incidence of metamorphosis the following summer. The incidence of metamorphosis was 53% in the ambient temperature regime (29/55) and only 2% (1/55) in the constant temperature regime. About 64% (7/11) of the presumptively metamorphic larvae in the ambient temperature regime entered metamorphosis compared with 10% (1/10) in the constant temperature regime. Our predictions of metamorphosis based on CF were consistent with the observation that seven presumptively metamorphic larvae (CF ≥ 1.50) metamorphosed in the ambient temperature regime and that there was no metamorphosis among presumptively nonmetamorphic larvae in the constant temperature regime. Significantly more presumptively nonmetamorphic larvae in the ambient regime entered metamorphosis and fewer presumptively metamorphic larvae (CF < 1.50) metamorphosed in the constant temperature regime than expected. We attribute this response to the effects of temperature on metabolic processes. Larval sea lampreys of the appropriate size (≥ 120 mm and ≥ 3.0 g) with a CF of 1.50 or greater in the fall will usually enter metamorphosis the following July, but the accuracy of these predictions may be improved in some populations by using an empirically determined CF criterion that reflects seasonal or population differences in mass–length relationships.

Transcriptome analysis of leafy spurge (Euphorbia esula) crown buds during shifts in well-defined phases of dormancy

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 821-827 ◽  
Author(s):  
David P. Horvath ◽  
James V. Anderson ◽  
Mauricio Soto-Suárez ◽  
Wun S. Chao
Keyword(s):  
Gene Expression ◽  
Gibberellic Acid ◽  
Microarray Analysis ◽  
Transcriptome Analysis ◽  
Seasonal Changes ◽  
Leafy Spurge ◽  
Euphorbia Esula ◽  
Ethylene Signaling ◽  
Root Buds

Microarray analysis was used to follow changes in gene expression coinciding with seasonal changes in the dormancy status of crown buds of field-grown leafy spurge. Known cold-regulated genes were induced, and numerous gibberellic acid–responsive genes were down-regulated during the transition from paradormancy to endodormancy. Genes involved in photomorphogenesis were induced during endodormancy. Also, ethylene signaling responses were observed during ecodormancy rather than endodormancy. These results provide additional insights into the signals regulating expression of several genes previously associated with transition from paradormancy to growth in root buds.

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