Effect of temperature on the growth of wheat. II. "Grass-clump" dwarfs and dwarf varieties

1969 ◽  
Vol 47 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Yun-te Yao ◽  
David T. Canvin

Six F1 "grass-clump" hybrids, two "grass-clump" selections, three normal varieties (Timstein, Redman, and Federation), and three dwarf varieties (Sonora 64, CB 151, and Norin 10) were grown in growth cabinets under 1200 ft-c of continuous light at various temperatures. The normal and dwarf varieties grew tallest at 16 °C and produced maximum shoot and seed yields at 16–19 °C.The Marquillo × Timstein "grass-clump" dwarf selection (F6) tillered extensively in temperature regimes that included 16 h of 16 °C in 24 h or 16 h of 21 °C and 8 h of 16 °C. Fertile tillers were produced in all temperature regimes except 16 °C. Growth at temperatures above 21 °C was essentially normal. The Redman × Federation "grass-clump" dwarf selection (F6) produced many tillers, but no fertile tillers when grown in a temperature regime that included 16 h of 16 °C. Fertile tillers were produced in all other temperature regimes, but extensive tillering was observed if the temperature treatment included 8 h of 16 °C. Completely normal growth was observed at temperatures above 26 °C.The six F1 "grass-clump" hybrids elongated and produced seed when grown at 30 °C.All "grass-clump" dwarf hybrids and dwarf selections investigated to date differ from normal varieties of wheat in that they are sterile dwarfs when grown at low temperature but grow essentially "normal" above a threshold temperature. Depending on the particular hybrid or selection the required temperature may be 21, 26, or 30 °C. In general, if the precise temperature requirements are not known, it appears probable that elongation and seed production by "grass-clump" dwarf can be induced by growing them under continuous light at 26 to 30 °C.

1980 ◽  
Vol 95 (1) ◽  
pp. 77-81 ◽  
Author(s):  
M. P. Fuller ◽  
C. F. Eagles

SummaryThe variation in hardening responses under different temperature regimes for three cultivars of Lolium perenne L. is described. The relative cold hardiness of the cultivars was modified by different temperatures during hardening. A threshold temperature existed above which hardening did not occur, but this temperature varied between cultivars.Although continuous low temperatures (2 °C) favoured hardening, hardening also occurred under warm day and cool night conditions (15:2 °C) where cultivars showed contrasting hardiness responses in daylengths of 16, 12 and 8 h. Under some of these conditions both leaf growth and hardiness were possible.The significance of these results is discussed in terms of the development of screening techniques and breeding objectives.


2016 ◽  
Vol 107 (1) ◽  
pp. 39-48 ◽  
Author(s):  
J. Glatz ◽  
H. du Plessis ◽  
J. Van den Berg

AbstractThe effect of temperature on the reproduction and development of Busseola fusca was studied under laboratory conditions. Single male–female pairs were confined to oviposition chambers kept at 15, 20, 26 and 30 ± 1°C and a 14L:10D photoperiod. Data on reproduction parameters were captured daily. Oviposition occurred at all the mentioned temperatures but no fertility was recorded at 30°C. The total number of eggs laid per female moth was between 300 and 400 and the optimum temperature for oviposition and fertility was between 20 and 26°C. Larval development was studied at five different temperature regimes, i.e. 15, 18, 20, 26 and 30 ± 1°C and a 14L:10D photoperiod. The most favourable temperature as well as the upper threshold temperature for larval development was between 26 and 30°C. Total development period was 152.6–52.6 days, respectively, at 15°C, and 26–30°C. The thermal constants for B. fusca was 99.50, 536.48, 246.25 and 893.66°D and lower temperature thresholds were 10.36, 8.14, 8.99 and 8.84°C, for completion of the egg, larval, pupal and egg-to-adult stages, respectively. Results on the thermal constants and lower and upper threshold temperatures of B. fusca can be used to predict the impact of climate change on the distribution and population growth of this pest.


1966 ◽  
Vol 49 (5) ◽  
pp. 989-1005 ◽  
Author(s):  
Richard Fitzhugh

In the squid giant axon, Sjodin and Mullins (1958), using 1 msec duration pulses, found a decrease of threshold with increasing temperature, while Guttman (1962), using 100 msec pulses, found an increase. Both results are qualitatively predicted by the Hodgkin-Huxley model. The threshold vs. temperature curve varies so much with the assumptions made regarding the temperature-dependence of the membrane ionic conductances that quantitative comparison between theory and experiment is not yet possible. For very short pulses, increasing temperature has two effects. (1) At lower temperatures the decrease of relaxation time of Na activation (m) relative to the electrical (RC) relaxation time favors excitation and decreases threshold. (2) For higher temperatures, effect (1) saturates, but the decreasing relaxation times of Na inactivation (h) and K activation (n) factor accommodation and increased threshold. The result is a U-shaped threshold temperature curve. R. Guttman has obtained such U-shaped curves for 50 µsec pulses. Assuming higher ionic conductances decreases the electrical relaxation time and shifts the curve to the right along the temperature axis. Making the conductances increase with temperature flattens the curve. Using very long pulses favors effect (2) over (1) and makes threshold increase monotonically with temperature.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Balseiro ◽  
Cecilia Laspoumaderes ◽  
Facundo Smufer ◽  
Laura Wolinski ◽  
Beatriz Modenutti

AbstractIn this study, we analysed how short term temperature fluctuation interacts with nutrient limitation in the vertical migrating Daphnia commutata. We hypothesize that short term (daily) temperature fluctuation will alleviate nutrient limitation. We carried out experiments analysing growth rates, phosphorus and RNA content of D. commutate grown under four different temperature regimes and two P-limited conditions. Our experiments showed that individuals grown under fluctuating temperature grew more than at the mean temperature. We estimated the expected sizes for the 15 °C treatment based on the Q10 and for the fluctuating temperature treatment. These expected sizes for both treatments resulted well below the observed ones. The P and RNA content of individuals grown at 10 °C were significantly higher than those at 20 °C, and when individuals grown at 10 °C were translocated to 20 °C they exerted an increased growth rate. Our results suggest that, under a regime of diel vertical migration, the temperature alternation would allow migrating organisms to alleviate the effect of severe nutrient limitation maintaining population growth. Under a scenario of global warming, where epilimnetic temperatures will increase, lake temperature will interact with nutrient limitation for consumers, but, organisms may be able to face these changes if they can still regularly move from a cold hypolimnion to a warmer epilimnion.


1992 ◽  
Vol 115 (1) ◽  
pp. 183-204 ◽  
Author(s):  
JORGE M. OLIVARES ◽  
NIKOLAOS A. PEPPAS

Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1695-1700 ◽  
Author(s):  
A. Murillo-Williams ◽  
G. P. Munkvold

Fusarium verticillioides causes seedling decay, stalk rot, ear rot, and mycotoxin contamination (primarily fumonisins) in maize. Systemic infection of maize plants by F. verticillioides can lead to kernel infection, but the frequency of this phenomenon has varied widely among experiments. Variation in the incidence of systemic infection has been attributed to environmental factors. In order to better understand the influence of environment, we investigated the effect of temperature on systemic development of F. verticillioides during vegetative and reproductive stages of plant development. Maize seeds were inoculated with a green fluorescent protein-expressing strain of F. verticillioides, and grown in growth chambers under three different temperature regimes. In the vegetative-stage and reproductive-stage experiments, plants were evaluated at tasseling (VT stage), and at physiological maturity (R6 stage), respectively. Independently of the temperature treatment, F. verticillioides was reisolated from nearly 100% of belowground plant tissues. Frequency of reisolation of the inoculated strain declined acropetally in aboveground internodes at all temperature regimes. At VT, the high-temperature treatment had the highest systemic development of F. verticillioides in aboveground tissues. At R6, incidence of systemic infection was greater at both the high- and low-temperature regimes than at the average-temperature regime. F. verticillioides was isolated from higher internodes in plants at R6, compared to stage VT. The seed-inoculated strain was recovered from kernels of mature plants, although incidence of kernel infection did not differ significantly among treatments. During the vegetative growth stages, temperature had a significant effect on systemic development of F. verticillioides in stalks. At R6, the fungus reached higher internodes in the high-temperature treatment, but temperature did not have an effect on the incidence of kernels (either symptomatic or asymptomatic) or ear peduncles infected with the inoculated strain. These results support the role of high temperatures in promoting systemic infection of maize by F. verticillioides, but plant-to-seed transmission may be limited by other environmental factors that interact with temperature during the reproductive stages.


1975 ◽  
Vol 107 (7) ◽  
pp. 775-779 ◽  
Author(s):  
Arthur M. Shapiro

AbstractPieris occidentalis nelsoni W. H. Edwards from Fairbanks, Alaska, was reared under a variety of photoperiod–temperature regimes. The source population is presumably univoltine and monophenic, with a phenotype resembling the vernal one produced by multivoltine, diphenic P. o. occidentalis Reakirt in Colorado and California. Photoperiods of 10 or 15 h produced 100% diapause pupae at 15 °C and circa 65% at 25 °C. Under continuous light 22% diapaused at 15 °C and < 1% at 25 °C. About 20% of non-diapause pupae produced adults resembling the estival phenotype of P. o. occidentalis, which is unknown in wild P. o. nelsoni. Although nelsoni is more likely to diapause than the nominate subspecies from the Sierra Nevada, its potential for direct development and polyphenism is interpreted as evidence that it is derived from a multivoltine ancestor.


Author(s):  
Jinmei Lu ◽  
Tiina Leiviskä ◽  
Ingar Walder

Abstract Dry covers can be applied above tailings to reduce and prevent formation of acid mine drainage and leaching of contaminants. Efficiency of covers is affected by different parameters, of which temperature change under climate change context is one. Here, a laboratory column leaching experiment was performed under four temperatures, 5, 10, 14, and 18 °C on unoxidized tailings from Ballangen, Norway. 600 mL of water was added to each column every second week and leachate collected and analyzed for pH, salinity, alkalinity, concentrations of sulfate, Co, Fe, Mn, Ni, and Zn. A thin layer of digested sewage sludge was added to columns after the 16th leaching cycle. In total, 21 leaching cycles were performed. Results showed low oxidation of tailings and therefore high pH and low salinity, SO42−, Fe, Ni, and Co in the leachates at leaching temperature of 5 °C. Addition of sludge cover slowed down oxidation of underlying tailings and decreased leaching of SO42−, Fe, Mn, Co, Ni, and Zn from the tailings deposit, especially at relatively high temperature. 10 °C is a threshold temperature, below which leaching is not affected by the cover addition so much. At a leaching temperature higher than 10 °C, the sludge cover addition can reduce the leaching of elements significantly.


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