scholarly journals Delayed Heading in Sorghum Varieties under High Temperature and Long Day-length Condition.

1997 ◽  
Vol 66 (3) ◽  
pp. 503-504 ◽  
Author(s):  
Junichi NAKANO ◽  
Takeshi YAMAGUCHI ◽  
Mitsuhiro TAKAYANAGI ◽  
Tadami TAKIGAMI
Keyword(s):  
High Temperature ◽  
Day Length ◽  
Long Day

Influence of Environment on Metabolism of Propanil in Rice

Weed Science ◽  
1971 ◽  
Vol 19 (5) ◽  
pp. 501-507 ◽  
Author(s):  
Richard H. Hodgson
Keyword(s):  
Oryza Sativa ◽  
High Temperature ◽  
High Growth ◽  
Dry Weight ◽  
Mean Value ◽  
Water Soluble ◽  
Day Length ◽  
Tissue Mass ◽  
Long Day ◽  
Root Treatment

The metabolism of 3′,4′-dichloropropionanilide (propanil) to 3,4-dichloroaniline (hereinafter referred to as 3,4-DCA) andN-(3,4-dichlorophenyl)glucosylamine (hereinafter referred to as 3,4-DCAG) was quantitatively modified in rice (Oryza sativaL. ‘Nato’) by temperature and day length. The propanil, 3,4-DCA, and 3,4-DCAG content of rice was determined 1, 2, 5, and 8 days after root treatment with 92 μM propanil. Plants were grown and treated under long-day (16 hr) and short-day (12 hr) conditions with day temperatures of 32, 27, or 21 C and night temperatures of 21 C. Absorption and metabolism of propanil were most rapid under high temperature and long day conditions. A mean value of 0.75 μmoles total of aniline equivalent per plant was obtained. Greater quantities of 3,4-DCA and 3,4-DCAG were recovered from plants in high temperature, long day environments. An average of 47% of the propanil plus water-soluble metabolites in rice was in root tissue. Conditions favoring high growth rates and transpiration increased the percentage in the shoots. Because of the increased tissue mass at high temperatures, mean concentrations of propanil plus water-soluble metabolites in plant tissue were reduced from 0.18 to 0.12 μmoles/g dry weight.

Influence of photoperiod and temperature on developmental time and number of molts in nymphs of two species of Odonata

1976 ◽  
Vol 54 (12) ◽  
pp. 2033-2045 ◽  
Author(s):  
Byron R. Ingram ◽  
Charles E. Jenner
Keyword(s):  
North Carolina ◽  
High Temperature ◽  
Developmental Time ◽  
Photoperiodic Response ◽  
Day Length ◽  
Long Day ◽  
Temperature Regimes ◽  
Photoperiodic Responses

Nymphs of the damselflies Enallagma hageni and Enallagma aspersum were collected in North Carolina from August to March and subjected to 11- and 14-h photoperiods at 16 and 21 °C. Development was generally completed more rapidly under long-day conditions. Under all day-length and temperature regimes, developmental time from the middle instars to emergence decreased from a maximum for those nymphs collected in August to a minimum for those collected in March. The two species had similar developmental times under long photoperiods at 21 °C; short photoperiods, however, were more inhibitory to the growth of E. hageni than to E. aspersum. The photoperiodic responses of E. hageni were similar at both temperatures, the developmental times being only slightly slower at 16 °C. In contrast, nymphs of E. aspersum kept at 16 °C showed no photoperiodic response. In both species, diapause or prolonged development occurred primarily in the two instars before the final, but not in the final itself.Extra molts usually accompanied slow developmental times in both species, regardless of photoperiod. The incidence of extra molting was greatest under conditions combining high temperature and short daylength. Extra molts were apparently common in field populations of E. aspersum, but were rare in those of E. hageni.

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.

Turions and dormancy states in Utricularia vulgaris

1979 ◽  
Vol 57 (24) ◽  
pp. 2740-2749 ◽  
Author(s):  
Robert D. Winston ◽  
Paul R. Gorham
Keyword(s):  
High Temperature ◽  
Dark Respiration ◽  
Starch Content ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Long Day ◽  
Response To Temperature ◽  
Late Stages ◽  
H 20 ◽  
Utricularia Vulgaris

Phenology and states of dormancy of Utricularia vulgaris were studied using plants and turions collected at intervals throughout the growing season of 1977 from a shallow eutrophic pond in central Alberta located at 53°25′ N, 113°46′ W. States of dormancy and the effects of photoperiod and temperature were determined by the potential for sprouting and subsequent apical growth under long-day (18 h, 20 °C), short-day (12 h, 20 °C), and high-temperature (16 h, 30 °C) conditions, with and without varying periods of chilling at 2–3 °C. Physiological changes associated with different states of dormancy such as frost hardiness, starch content, and dark respiration were also investigated. Turions were formed 1 month after summer solstice and entered a state of innate dormancy during which only a high-temperature treatment at 30 °C would induce sprouting. Plants from innately dormant turions that were forced to sprout and were then cultured at 20 °C invariably reentered dormancy by the production of new turions. Turions collected in the late stages of innate dormancy could withstand −8 °C but not −12 °C. As temperatures dropped and ice cover became continuous, turions entered an imposed state of dormancy during which immediate sprouting and continued vegetative growth occurred under all conditions. Starch content reached a maximum of 49 mg g−1 fresh weight during early innate dormancy and declined steadily thereafter. Dark respiration in response to temperature of plants obtained from turions collected during innate and imposed dormancy states differed above 25 °C but was similar below.

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.

Flowering responses to vernalization and photoperiod in annual medics (Medicago spp.)

1975 ◽  
Vol 26 (5) ◽  
pp. 831 ◽  
Author(s):  
NM Clarkson ◽  
JS Russell
Keyword(s):  
High Temperature ◽  
Flowering Time ◽  
Vernalization Requirement ◽  
Vernalization Response ◽  
The Third ◽  
Long Day ◽  
Temperature Requirement ◽  
New Finding ◽  
Annual Medics

The three processes thought to control flowering times in annual medics (Medicago spp.) are a vernalization requirement, a long day requirement and a high temperature requirement. To examine the first two processes, seed of seven cultivars of six species was vernalized at 1�C for periods of up to 11 weeks, then grown to flowering under three photoperiods in a glasshouse. To study the third process, the time to flowering of selected treatments from this expcrirnent was compared with flowering data from plants grown in the field at a range of temperatures lower than in the glasshouse. Vernalization and photoperiod caused large shifts in flowering time but the effects varied widely among species. M. scutellata was almost insensitive to both factors but in M. rugosa acceleration of up to 91 days was caused by treatment. Vernalization and short dark periods were additive in accelerating flowering and largely able to substitute for each other. Species flowered almost simultaneously when given their most favourable conditions for flowering. High temperature accelerated flowering in all species studied. However, in species other than M. scutellata it was necessary for a vernalization requirement to be met before this effect was observed. A new finding was that the vernalization response in M. truncatula and M. littoralis was largely reversed after more than 7 weeks of vernalization. This suggests a previously undetected flowering mechanism in these species.

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.

Hochelaga lettuce

2008 ◽  
Vol 88 (3) ◽  
pp. 551-553 ◽  
Author(s):  
Sylvie Jenni ◽  
George C Emery
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Organic Soil ◽  
Organic Soils ◽  
Physiological Disorder ◽  
Long Day ◽  
Lactuca Sativa L ◽  
Lettuce Breeding ◽  
Growing Conditions ◽  
Horticultural Research

Hochelaga is an early and heavy crisphead lettuce highly tolerant to bolting under long-day growing conditions (more than 13-h). Hochelaga is the first variety released by the Horticultural Research and Development Centre (HRDC) lettuce breeding program of Agriculture and Agri-Food Canada (AAFC), Saint-Jean-sur-Richelieu, Quebec. Very similar in appearance to Ithaca, the regional standard, Hochelaga is well adapted to organic soils. Hochelaga is more tolerant than Ithaca to rib discoloration, a physiological disorder caused by high-temperature growing conditions. Key words: Lactuca sativa L., crisphead lettuce, rib discoloration, bolting, heat stress, organic soil

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