Effects of short-term temperature fluctuations on leaf photosynthesis in corn (Zea mays)

1979 ◽  
Vol 57 (21) ◽  
pp. 2387-2393 ◽  
Author(s):  
M. R. Thiagarajah ◽  
L. A. Hunt ◽  
R. B. Hunter
Keyword(s):  
Zea Mays ◽  
Low Temperature ◽  
Temperature Stability ◽  
Temperature Fluctuations ◽  
Complete Recovery ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Genotypic Differences ◽  
Short Term ◽  
Low Temperature Treatment

The effects of short-term temperature fluctuations on net photosynthetic rates (Pn) are described for a single-cross corn (Zea mays L.) hybrid (Harrow 691). The hybrid was grown at 25 °C and subjected to 4 days at either 15 or35 °C, and then maintained at 25 °C. Genotypic differences in tolerance of Pn to low temperature were studied using 12 hybrids of different maturities grown at 25 °C and subjected to 4 days at 15 °C.Following low temperature treatment. Pn was initially reduced by about 15% for leaves 5. 9. and 13 of hybrid Harrow 691. but completely recovered after 1 day at 25 °C. Following high temperature treatment, leaves 5 and 9 showed similar reductions in Pn whereas leaf 13 was not affected. The photosynthetic activity of the heat-stressed leaf 9 recovered after 1 day, but that of leaf 5 showed no recovery for 14 days at 25 °C.Among 12 hybrids. Pn of the newly matured leaf 7 was reduced after the low temperature treatment, but the reduction was more drastic for two late hybrids than for three early hybrids. Most hybrids showed complete recovery of Pn after 1 day at 25 °C. but genotypic differences were evident. The results reported indicate that further evaluation of the amount of genetic variation in temperature stability in corn could be carried out usefully.

EFFECTS OF 10- AND 20-HOUR PHOTOPERIOD TREATMENTS AT 20 AND 30 C ON RATE OF DEVELOPMENT OF A SINGLE-CROSS MAIZE (ZEA MAYS) HYBRID

1976 ◽  
Vol 56 (4) ◽  
pp. 795-798 ◽  
Author(s):  
C. M. BREUER ◽  
R. B. HUNTER ◽  
L. W. KANNENBERG
Keyword(s):  
Zea Mays ◽  
Low Temperature ◽  
Grain Filling ◽  
Temperature Treatment ◽  
Rate Of Development ◽  
Low Temperature Treatment ◽  
Single Cross ◽  
Grain Filling Period ◽  
Temperature Interaction ◽  
Time Required

A single-cross maize (Zea mays L.) hybrid was grown under two photoperiods (10 and 20 h) at two constant temperatures (20 and 30 C). Rate of development was characterized by the number of days from planting to tassel initiation, tassel initiation to silking, and silking to maturity. Long photoperiod and low temperature independently increased the number of days between planting and tassel initiation. The interval between tassel initiation and silking was not affected by photoperiod, but was increased significantly by the low temperature treatment. During the grain filling period (silking to maturity), temperature had the principal effect, but a photoperiod by temperature interaction did occur. Although plants grown at 20 C required more days to reach maturity than those grown at 30 C, the filling period at 20 C was shorter under the 10-h photoperiod than under the 20-h photoperiod, but at 30 C, the 10-h photoperiod treatment had the longer filling period. The delay in development at the low temperature, although apparent at all three stages of development, was not of the same magnitude. When the delay in development at 20 C is expressed as a percent of time required at 30 C, the 20 C treatment took 28% longer between planting and tassel initiation than the 30 C treatment. The corresponding figures for days between tassel initiation and silking and between silking and maturity were 58 and 46%, respectively.

scholarly journals Peculiarities of a glass-sludge mixture subjected to low-temperature treatment

2017 ◽  
Vol 49 (3) ◽  
pp. 207-224 ◽  
Author(s):  
Parra Parra ◽  
Marina Vlasova ◽  
Aguilar Márquez ◽  
Tamara Tomila
Keyword(s):  
Aqueous Solution ◽  
Low Temperature ◽  
Temperature Treatment ◽  
Adsorption Properties ◽  
Glass Shell ◽  
Short Term ◽  
Active Sludge ◽  
Low Temperature Treatment ◽  
Treatment Conditions ◽  
Sewage Purification

In this work, the specific features of formation of a composite material consisting of a mixture of low-melting ground glass and waste active sludge, which is used for sewage purification, have been considered. It has been established that, after low-temperature (600-700?C) short-term (30-60 min) treatment, specimens consist of a porous glass shell and a core saturated by carbon form. With change in temperature treatment conditions, the thickness and porosity of the shell and the size of the carbonized core change, leading to different absorption and adsorption properties. Due to the presence of a carbon-containing core, specimens absorb efficiently methylene blue (MB) from aqueous solution.

Endometrial Thermal Balloon Ablation Using a High Temperature, Pulsed System: A Mathematical Model

2003 ◽  
Vol 125 (6) ◽  
pp. 841-851 ◽  
Author(s):  
Daniel M. Reinders ◽  
Susan A. Baldwin ◽  
Joel L. Bert
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Treatment Time ◽  
Uterine Cavity ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Low Temperature Treatment ◽  
Balloon Ablation ◽  
Pulsed Treatment ◽  
Thermal Balloon

A new endometrial thermal balloon ablation treatment for menorrhagia is modeled mathematically to predict its efficacy and safety. A device preheats a fluid to 173°C within a reservoir external to the uterus, and then pulses this fluid without further heating between the reservoir and the balloon for 2.1 min of treatment time. The model predicted this treatment to result in consistent immediate tissue death (coagulation) depths of 3.4±0.1 mm for uterine cavities of 7 to 26 mL, and that eventual necrosis (tissue death that would occur 1–5 days post burn) may occur to depths of 6.5±0.2 mm. Whereas, burn depths varied with uterine cavity volume when a low temperature treatment (constant 75°C for 15 min) was modeled (2.3–2.9 mm and 6.8–8.2 mm, for immediate tissue death and eventual necrosis respectively). Similarly, the high temperature, pulsed treatment was less sensitive to blood perfusion rate than the low temperature treatment. Predicted eventual necrosis depth was 1.5 mm less for the high temperature, pulsed treatment than that predicted for a low temperature treatment (constant 87°C for 7 min) for the same immediate tissue death depth (3.5 mm), indicating that the new high temperature treatment may result in less damage to non targeted tissues.

Studies on Freshwater Osmoregulation in the Ammocoete larva of Lampetra Planeri (Bloch)

1968 ◽  
Vol 48 (3) ◽  
pp. 597-609
Author(s):  
R. MORRIS ◽  
J. M. BULL
Keyword(s):  
Low Temperature ◽  
Extracellular Space ◽  
Ringer Solution ◽  
Temperature Treatment ◽  
Sodium Influx ◽  
Sodium Chloride Solutions ◽  
Low Temperature Treatment ◽  
Lampetra Planeri ◽  
Equilibrium Concentrations ◽  
Sodium Loss

1. An investigation has been made of the factors which cause sodium loss from ammocoetes when they are immersed in de-ionized water at 1° and 10° C. 2. Sodium influx ceases when animals are first immersed in de-ionized water, but can recommence when the animal loses sufficient sodium to the environment. The concentration of sodium required for influx to take place decreases with succeeding periods of immersion in de-ionized water at 10° C. and reaches minimum equilibrium concentrations as low as 0.005 mM-Na/l. 3. Low temperature inhibits sodium influx and thus promotes net loss of sodium to de-ionized water. 4. Low temperature also decreases the initial loss of sodium to de-ionized water and probably lowers the permeability of the external surfaces of the animal to ions. This effect is small compared with the inhibition of ion uptake so that the combined result is to increase the net loss of sodium from the animal. 5. Since animals lose calcium to de-ionized water and show a decreased rate of sodium loss when calcium salts are added, it is believed that the high rates of sodium loss in de-ionized water are attributable to the effect of calcium on permeability. 6. Lack of calcium may also explain why animals which have been depleted of sodium by low-temperature treatment take up sodium much faster at higher temperatures from dilute Ringer solutions than from pure sodium chloride solutions. 7. When animals lose ions to de-ionized water at low temperature, sodium and chloride are lost from the extracellular space, whilst the muscle cells lose potassium. These ions are recovered into the extracellular space when animals are allowed to take up ions at 10° C. from diluted Ringer solution later.

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