scholarly journals Long day plants and the response to global warming: rapid evolutionary change in day length sensitivity is possible in wild beet

2007 ◽  
Vol 20 (1) ◽  
pp. 349-357 ◽  
Author(s):  
H. VAN DIJK ◽  
N. HAUTEKÈETE
Keyword(s):  
Global Warming ◽  
Evolutionary Change ◽  
Day Length ◽  
Long Day ◽  
Wild Beet ◽  
Long Day Plants ◽  
Rapid Evolutionary Change

scholarly journals Reversion of the photoperiod dependence of flowering in rice with synthetic Hd1-microProteins

2018 ◽  
Author(s):  
Tenai Eguen ◽  
Jorge Gomez Ariza ◽  
Kaushal Kumar Bhati ◽  
Bin Sun ◽  
Fabio Fornara ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Heading Date ◽  
Day Length ◽  
Dependent Manner ◽  
Yield Analysis ◽  
Rice Plants ◽  
Short Day ◽  
Long Day ◽  
Long Day Plants

SUMMARYRice (Oryza sativa) is a facultative short-day plant that flowers very late when grown in non-inductive long day conditions. Photoperiod-dependent flowering in rice is regulated by heading date (Hd1) which acts as both an activator and repressor of flowering in a day length-dependent manner. In order to regulate flowering of rice in long days (LD), overexpression of a synthetic Hd1miP, which is capable of interacting with Hd1, was employed. Transgenic Hd1miP rice plants flowered significantly earlier when grown in LD compared to SD, showing that synthetic microProteins can be used to revert short-day plants to long-day plants. Yield analysis revealed that although the OX-Hd1miP grains are comparable to WT in terms of the size of the grains produced, OX-Hd1miP plants like hd1 knockout plants, are compromised in the number of grains produced and the grain maturity rate, suggesting an additional unrecognized role of Hd1 in grain maturity.

scholarly journals Eco-evolutionary dynamics

2009 ◽  
Vol 364 (1523) ◽  
pp. 1483-1489 ◽  
Author(s):  
F. Pelletier ◽  
D. Garant ◽  
A.P. Hendry
Keyword(s):  
Time Scale ◽  
Evolutionary Dynamics ◽  
Evolutionary Change ◽  
Ecological Change ◽  
Evolutionary Changes ◽  
Microevolutionary Change ◽  
Theoretical Developments ◽  
Rapid Evolutionary Change

Evolutionary ecologists and population biologists have recently considered that ecological and evolutionary changes are intimately linked and can occur on the same time-scale. Recent theoretical developments have shown how the feedback between ecological and evolutionary dynamics can be linked, and there are now empirical demonstrations showing that ecological change can lead to rapid evolutionary change. We also have evidence that microevolutionary change can leave an ecological signature. We are at a stage where the integration of ecology and evolution is a necessary step towards major advances in our understanding of the processes that shape and maintain biodiversity. This special feature about ‘eco-evolutionary dynamics’ brings together biologists from empirical and theoretical backgrounds to bridge the gap between ecology and evolution and provide a series of contributions aimed at quantifying the interactions between these fundamental processes.

scholarly journals Day Length and Weather Effects on Children’s Physical Activity and Participation in Play, Sports, and Active Travel

2012 ◽  
Vol 9 (8) ◽  
pp. 1105-1116 ◽  
Author(s):  
Anna Goodman ◽  
James Paskins ◽  
Roger Mackett
Keyword(s):  
Physical Activity ◽  
Cloud Cover ◽  
Objective Measure ◽  
Active Travel ◽  
Day Length ◽  
Physically Active ◽  
The Public ◽  
Daylight Saving ◽  
Long Day ◽  
Children’S Physical Activity

Background:Children in primary school are more physically active in the spring/summer. Little is known about the relative contributions of day length and weather, however, or about the underlying behavioral mediators.Methods:325 British children aged 8 to 11 wore accelerometers as an objective measure of physical activity, measured in terms of mean activity counts. Children simultaneously completed diaries in which we identified episodes of out-of-home play, structured sports, and active travel. Our main exposure measures were day length, temperature, rainfall, cloud cover, and wind speed.Results:Overall physical activity was higher on long days (≥ 14 hours daylight), but there was no difference between short (< 9.5 hours) and medium days (10.2–12.6 hours). The effect of long day length was largest between 5 PM and 8 PM, and persisted after adjusting for rainfall, cloud cover, and wind. Up to half this effect was explained by a greater duration and intensity of out-of-home play on long days; structured sports and active travel were less affected by day length.Conclusions:At least above a certain threshold, longer afternoon/evening daylight may have a causal role in increasing child physical activity. This strengthens the public health arguments for daylight saving measures such as those recently under consideration in Britain.

scholarly journals Prior exposure to long-day photoperiods alters immune responses and increases susceptibility to parasitic infection in stickleback

2020 ◽  
Vol 287 (1930) ◽  
pp. 20201017
Author(s):  
James R. Whiting ◽  
Muayad A. Mahmud ◽  
Janette E. Bradley ◽  
Andrew D. C. MacColl
Keyword(s):  
Immune Responses ◽  
Parasitic Infection ◽  
Population Variation ◽  
Host Susceptibility ◽  
Day Length ◽  
Previous Exposure ◽  
Parasite Abundance ◽  
Susceptibility To Infection ◽  
Long Day ◽  
Host Parasite

Seasonal disease and parasitic infection are common across organisms, including humans, and there is increasing evidence for intrinsic seasonal variation in immune systems. Changes are orchestrated through organisms' physiological clocks using cues such as day length. Ample research in diverse taxa has demonstrated multiple immune responses are modulated by photoperiod, but to date, there have been few experimental demonstrations that photoperiod cues alter susceptibility to infection. We investigated the interactions among photoperiod history, immunity and susceptibility in laboratory-bred three-spined stickleback (a long-day breeding fish) and its external, directly reproducing monogenean parasite Gyrodactylus gasterostei . We demonstrate that previous exposure to long-day photoperiods (PLD) increases susceptibility to infection relative to previous exposure to short days (PSD), and modifies the response to infection for the mucin gene muc2 and Treg cytokine foxp3a in skin tissues in an intermediate 12 L : 12 D photoperiod experimental trial. Expression of skin muc2 is reduced in PLD fish, and negatively associated with parasite abundance. We also observe inflammatory gene expression variation associated with natural inter-population variation in resistance, but find that photoperiod modulation of susceptibility is consistent across host populations. Thus, photoperiod modulation of the response to infection is important for host susceptibility, highlighting new mechanisms affecting seasonality of host–parasite interactions.

Natural hybridization as a catalyst of rapid evolutionary change

2012 ◽  
pp. 256-265 ◽  
Author(s):  
Michael L. Arnold ◽  
Jennafer A.P. Hamlin ◽  
Amanda N. Brothers ◽  
Evangeline S. Ballerini
Keyword(s):  
Evolutionary Change ◽  
Natural Hybridization ◽  
Rapid Evolutionary Change

Environmental influences on light and dark CO2 fixation by Kalanchoe daigremontiana

1975 ◽  
Vol 53 (11) ◽  
pp. 1132-1138 ◽  
Author(s):  
E. Nalborczyk ◽  
L. J. Lacroix ◽  
R. D. Hill
Keyword(s):  
Co2 Fixation ◽  
Red Light ◽  
Day Length ◽  
Low Oxygen ◽  
Long Day ◽  
C Value ◽  
Warm Night ◽  
Dark Co2 Fixation ◽  
Kalanchoë Daigremontiana ◽  
Kalanchoe Daigremontiana

The influence of day length, light quality, temperature, drought, and oxygen concentration on gas exchange of Kalanchoe daigremontiana was investigated. The ratio of photosynthesis to dark CO2 fixation with plants under a long-day and short-warm-night regime was 2.0 and under a short-day and long-cool-night regime, 0.2. With drought conditions this value may be less than 0.02. Under low oxygen concentrations high photosynthetic rates of about 20 mg CO2 dm−2 h−1 were observed with a compensation point of about 20 ppm. Restricting CO2 supply to dark periods produced plants with a δ13C value of −10.6‰. Restricting CO2 supply to light periods gave a δ13C value of −25.9‰, whereas no control of CO2 gave δ13C values of −15‰. The data obtained suggest that variations in δ13C values in Kalanchoe result from changes in the proportion of light and dark CO2 fixation.Far-red light and oxygen promoted the release of CO2 from Kalanchoe after the plants had undergone a period of dark CO2 fixation. Maximum release occurred within about 1 h. The effect could be reversed by removal of either far-red light or oxygen. Decreases in the acidity of the plants accompanied CO2 release, which indicated that decarboxylation of a C4 acid was the source of the CO2.

Hypoglycemia and torpor in Siberian hamsters

1999 ◽  
Vol 276 (3) ◽  
pp. R776-R781 ◽  
Author(s):  
John Dark ◽  
Daniel A. Lewis ◽  
Irving Zucker
Keyword(s):  
Blood Glucose ◽  
Body Temperature ◽  
Body Mass ◽  
Air Temperature ◽  
Day Length ◽  
Siberian Hamsters ◽  
Long Day ◽  
Necessary And Sufficient ◽  
Blood Glucose Concentrations ◽  
Torpor Bouts

We tested whether reduced blood glucose concentrations are necessary and sufficient for initiation of torpor in Siberian hamsters. During spontaneous torpor bouts, body temperature (Tb) decreases from the euthermic value of 37 to <31°C. Among hamsters that displayed torpor during maintenance in a short-day length (10 h light/day) at an air temperature of 15°C, blood glucose concentrations decreased significantly by 28% as Tb fell from 37 to <31°C and increased during rewarming so that by the time Tb first was >36°C, glucose concentrations had returned to the value preceding torpor. Hamsters did not display torpor when maintained in a long-day length (16 h light/day) and injected with a range of insulin doses (1–50 U/kg body mass), some of which resulted in sustained, pronounced hypoglycemia. We conclude that changes in blood glucose concentrations may be a consequence rather than a cause of the torpid state and question whether induction of torpor by 2-deoxy-d-glucose is due to its general glucoprivic actions.

Variability in photoperiod and the inhibition of flowering in a high latitude population of Saxifraga rivularis

1981 ◽  
Vol 59 (3) ◽  
pp. 388-391 ◽  
Author(s):  
J. A. Teeri ◽  
S. J. Tonsor
Keyword(s):  
High Latitude ◽  
High Intensity ◽  
Dark Period ◽  
Controlled Environment ◽  
Photoperiodic Control ◽  
Incandescent Light ◽  
Devon Island ◽  
Low Intensity ◽  
Long Day ◽  
Long Day Plants

A population of Saxifraga rivularis L. collected at Truelove Lowland, Devon Island, N.W.T., Canada (75°41′ N) exhibits a photoperiodic control of flowering in controlled environment chambers. The plants respond in a manner typical of long-day plants with flowering inhibited by either a 6-h daily dark period, or by a 6-h daily low intensity irradiance regime of incandescent light. The inhibition of flowering by 6 h day−1 of incandescent light does not occur if the incandescent light is given in twelve 0.5-h doses, each followed by 1 h of red-rich high intensity irradiance.

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