scholarly journals Brassinosteroids and the Tolerance of Cereals to Low and High Temperature Stress: Photosynthesis and the Physicochemical Properties of Cell Membranes

2021 ◽  
Vol 23 (1) ◽  
pp. 342
Author(s):  
Iwona Sadura ◽  
Anna Janeczko
Keyword(s):  
High Temperature ◽  
Temperature Stress ◽  
High Temperatures ◽  
Low Temperatures ◽  
Sugar Content ◽  
Frost Tolerance ◽  
Plant Production ◽  
Membrane Properties ◽  
Winter Rye ◽  
The Impact

Cereals, which belong to the Poaceae family, are the most economically important group of plants. Among abiotic stresses, temperature stresses are a serious and at the same time unpredictable problem for plant production. Both frost (in the case of winter cereals) and high temperatures in summer (especially combined with a water deficit in the soil) can result in significant yield losses. Plants have developed various adaptive mechanisms that have enabled them to survive periods of extreme temperatures. The processes of acclimation to low and high temperatures are controlled, among others, by phytohormones. The current review is devoted to the role of brassinosteroids (BR) in cereal acclimation to temperature stress with special attention being paid to the impact of BR on photosynthesis and the membrane properties. In cereals, the exogenous application of BR increases frost tolerance (winter rye, winter wheat), tolerance to cold (maize) and tolerance to a high temperature (rice). Disturbances in BR biosynthesis and signaling are accompanied by a decrease in frost tolerance but unexpectedly an improvement of tolerance to high temperature (barley). BR exogenous treatment increases the efficiency of the photosynthetic light reactions under various temperature conditions (winter rye, barley, rice), but interestingly, BR mutants with disturbances in BR biosynthesis are also characterized by an increased efficiency of PSII (barley). BR regulate the sugar metabolism including an increase in the sugar content, which is of key importance for acclimation, especially to low temperatures (winter rye, barley, maize). BR either participate in the temperature-dependent regulation of fatty acid biosynthesis or control the processes that are responsible for the transport or incorporation of the fatty acids into the membranes, which influences membrane fluidity (and subsequently the tolerance to high/low temperatures) (barley). BR may be one of the players, along with gibberellins or ABA, in acquiring tolerance to temperature stress in cereals (particularly important for the acclimation of cereals to low temperature).

scholarly journals Plastic responses of survival and fertility following heat stress in pupal and adult Drosophila virilis

2021 ◽  
Author(s):  
Benjamin Walsh ◽  
Steven Parratt ◽  
Natasha Mannion ◽  
Rhonda Snook ◽  
Amanda Bretman ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Temperature Stress ◽  
High Temperatures ◽  
Male Fertility ◽  
Thermal Tolerance ◽  
Drosophila Virilis ◽  
Life History Stage ◽  
Heat Hardening ◽  
The Impact

The impact of rising global temperatures on survival and reproduction is putting many species at risk of extinction. In particular, it has recently been shown that thermal effects on reproduction, especially limits to male fertility, can underpin species distributions in insects. However, the physiological factors influencing fertility at high temperatures are poorly understood. Key factors that affect somatic thermal tolerance such as hardening, the ability to phenotypically increase thermal tolerance after a mild heat shock, and the differential impact of temperature on different life stages, are largely unexplored for thermal fertility tolerance. Here, we examine the impact of high temperatures on male fertility in the cosmopolitan fruit fly Drosophila virilis. We first determined whether temperature stress at either the pupal or adult life-history stage impacts fertility. We then tested the capacity for heat-hardening to mitigate heat-induced sterility. We found that thermal stress reduces fertility in different ways in pupae and adults. Pupal heat stress delays sexual maturity, whereas males heated as adults can reproduce initially following heat stress, but lose the ability to produce offspring. We also found evidence that while heat-hardening in D. virilis can improve high temperature survival, there is no significant protective impact of this same hardening treatment on fertility. These results suggest that males may be unable to prevent the costs of high temperature stress on fertility through heat-hardening which limits a species’ ability to quickly and effectively reduce fertility loss in the face of short-term high temperature events.

scholarly journals Alterations of Endogenous Hormones, Antioxidant Metabolism, and Aquaporin Gene Expression in Relation to γ-Aminobutyric Acid-Regulated Thermotolerance in White Clover

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1099
Author(s):  
Hongyin Qi ◽  
Dingfan Kang ◽  
Weihang Zeng ◽  
Muhammad Jawad Hassan ◽  
Yan Peng ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Temperature ◽  
Temperature Stress ◽  
White Clover ◽  
High Temperature Stress ◽  
Aminobutyric Acid ◽  
Endogenous Hormones ◽  
Gaba Level ◽  
Antioxidant Metabolism ◽  
The Impact

Persistent high temperature decreases the yield and quality of crops, including many important herbs. White clover (Trifolium repens) is a perennial herb with high feeding and medicinal value, but is sensitive to temperatures above 30 °C. The present study was conducted to elucidate the impact of changes in endogenous γ-aminobutyric acid (GABA) level by exogenous GABA pretreatment on heat tolerance of white clover, associated with alterations in endogenous hormones, antioxidant metabolism, and aquaporin-related gene expression in root and leaf of white clover plants under high-temperature stress. Our results reveal that improvement in endogenous GABA level in leaf and root by GABA pretreatment could significantly alleviate the damage to white clover during high-temperature stress, as demonstrated by enhancements in cell membrane stability, photosynthetic capacity, and osmotic adjustment ability, as well as lower oxidative damage and chlorophyll loss. The GABA significantly enhanced gene expression and enzyme activities involved in antioxidant defense, including superoxide dismutase, catalase, peroxidase, and key enzymes of the ascorbic acid–glutathione cycle, thus reducing the accumulation of reactive oxygen species and the oxidative injury to membrane lipids and proteins. The GABA also increased endogenous indole-3-acetic acid content in roots and leaves and cytokinin content in leaves, associated with growth maintenance and reduced leaf senescence under heat stress. The GABA significantly upregulated the expression of PIP1-1 and PIP2-7 in leaves and the TIP2-1 expression in leaves and roots under high temperature, and also alleviated the heat-induced inhibition of PIP1-1, PIP2-2, TIP2-2, and NIP1-2 expression in roots, which could help to improve the water transportation and homeostasis from roots to leaves. In addition, the GABA-induced aquaporins expression and decline in endogenous abscisic acid level could improve the heat dissipation capacity through maintaining higher stomatal opening and transpiration in white clovers under high-temperature stress.

Analysis of Ferroelectric Microcapacitors by Scanning Probe Microscope

2004 ◽  
Vol 811 ◽  
Author(s):  
Nobuhiro Kin ◽  
Koichiro Honda
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Evaluation System ◽  
Ferroelectric Material ◽  
Scanning Probe Microscope ◽  
Scanning Probe ◽  
Electrical Heater ◽  
Device Processing ◽  
Probe Microscope ◽  
The Impact

ABSTRACTTo develop higher density FRAM requires reducing cell size. Therefore, the size effects resulting from device processing and the material's physical properties must be measured. Therefore, analyzing the electric characteristics of a single bit cell capacitor has become important. Two known characteristics of ferroelectric material are that the Vc increases at low temperatures, and the Pr falls at high temperatures. To further evaluate the impact of temperature on ferroelectrics, we constructed a new evaluation system based on a scanning probe microscope, that can measure the electric characteristics of a single bit cell capacitor. This system can be used in the temperature range from −120 degrees to 300 degrees C. We accomplished this by circulating liquid nitrogen around a SPM stage and by using an electrical heater. We measured the electrical properties of ferroelectric microcapacitors by using a sample with IrOx/PZT/Pt structure. Our measurements revealed that 2Pr really increases at low temperatures, and Pr decreases at high temperatures. That is, we have shown that Vc increases 30% at low temperatures and Pr decreases 10% also in an actual FRAM single bit cell capacitor.

1700V, 5.5mOhm-cm2 4H-SiC DMOSFET with Stable 225°C Operation

2014 ◽  
Vol 778-780 ◽  
pp. 903-906 ◽  
Author(s):  
Kevin Matocha ◽  
Kiran Chatty ◽  
Sujit Banerjee ◽  
Larry B. Rowland
Keyword(s):  
High Temperature ◽  
Temperature Stress ◽  
High Temperatures ◽  
Threshold Voltage ◽  
Room Temperature ◽  
Gate Bias ◽  
Threshold Voltage Shift ◽  
Device Reliability ◽  
Bias Temperature Stress ◽  
High Temperature Operation

We report a 1700V, 5.5mΩ-cm24H-SiC DMOSFET capable of 225°C operation. The specific on-resistance of the DMOSFET designed for 1200V applications is 8.8mΩ-cm2at 225°C, an increase of only 60% compared to the room temperature value. The low specific on-resistance at high temperatures enables a smaller die size for high temperature operation. Under a negative gate bias temperature stress (BTS) at VGS=-15 V at 225°C for 20 minutes, the devices show a threshold voltage shift of ΔVTH=-0.25 V demonstrating one of the key device reliability requirements for high temperature operation.

scholarly journals Forging, textures, and deformation systems in a B2 FeAl alloy

1999 ◽  
Vol 14 (3) ◽  
pp. 715-728 ◽  
Author(s):  
P. Zhao ◽  
D. G. Morris ◽  
M. A. Morris Munoz
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Slip System ◽  
High Temperatures ◽  
Low Temperatures ◽  
High Speed ◽  
Deformation Texture ◽  
Slip Systems ◽  
Feal Alloy ◽  
Very High

High-temperature forging experiments have been carried out by axial compression testing on a Fe–41Al–2Cr alloy in order to determine the deformation systems operating under such high-speed, high-temperature conditions, and to examine the textures produced by such deformation and during subsequent annealing to recrystallize. Deformation is deduced to take place by the operation of 〈111〉 {110} and 〈111〉{112} slip systems at low temperatures and by 〈100〉{001} and 〈100〉{011} slip systems at high temperatures, with the formation of the expected strong 〈111〉 textures. The examination of the weak 〈100〉 texture component is critical to distinguishing the operating slip system. Both texture and dislocation analyses are consistent with the operation of these deformation systems. Recrystallization takes place extremely quickly at high temperatures (above 800 °C), that is within seconds after deformation and also dynamically during deformation itself. Recrystallization changes the texture such that 〈100〉 textures superimpose on the deformation texture. The flow stress peak observed during forging is found at a very high temperature. Possible origins of the peak are examined in terms of the operating slip systems.

Applications: Light My Fire

1982 ◽  
Vol 75 (1) ◽  
pp. 53-55
Author(s):  
George Knill ◽  
George Fawceti
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Low Temperatures ◽  
Chemical Process ◽  
Room Temperature ◽  
Very High

Everyone knows that wood bums at a very high temperature. This burning is a chemical process that combines oxygen and carbon. The process occurs at very low temperatures as well as at very high ones. At high temperatures the process is spectacular-fire. At low temperatures (room temperature) you won’t even notice it, although it is still going on. Wood is always burning.

Investigation of Impact Compressive Mechanical Properties of Sandstone After as well as Under High Temperature

2014 ◽  
Vol 33 (6) ◽  
pp. 585-591 ◽  
Author(s):  
Shi Liu ◽  
Jinyu Xu
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Critical Temperature ◽  
High Temperatures ◽  
Experimental Studies ◽  
Practical Significance ◽  
Temperature Environment ◽  
Shpb Test ◽  
The Impact ◽  
High Temperature Environment

AbstractConducting experimental studies on the impact compressive mechanical properties of rock under the high temperature environment is of both theoretical value and practical significance to understanding the relationship between the rock under the effect of impact loads and the high temperature environment. Based on the Φ100 mm SHPB and the self-developed Φ100 mm high-temperature SHPB test devices, the impact compressive tests on the sandstone, whether cooling after high temperatures or under real-time high temperatures are carried out. As the test results indicate that since the two high-temperature ways of loading are different from each other, the impact compressive properties of sandstone, after as well as under high temperatures, show different variations along with changes in temperature. Under the effect of the same impact loading rate, there exists a clear critical temperature range in the impact compressive mechanical properties of sandstone after high temperature, and, near the critical temperature, there occurs a significant mutation in the impact compressive mechanical properties. Under high temperatures, however, the impact compressive mechanical properties follow an overall continuity of change except that there are slight fluctuations at individual temperatures.

scholarly journals Growth, flowering and fruiting in tomatoes in relation to temperature, cycocel and GA.

1970 ◽  
Vol 18 (2) ◽  
pp. 105-110
Author(s):  
A.A. Abdalla ◽  
K. Verkerk
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
High Temperatures ◽  
Root Development ◽  
Temperature Regime ◽  
Low Temperatures ◽  
Fruit Set ◽  
High Temperature Regime ◽  
Temperature Regimes ◽  
Dark Green

The effects were assessed of CCC and GA on tomatoes grown either under a high temperature regime (35 degrees day and 25 degrees C. night) or at normal temperatures (22 degrees and 18 degrees ). CCC (0.4%) was applied to the soil in the pots either 2 days after transplanting or at the start of flowering; G A was applied by dipping the first truss in GA (50 p.p.m.). CCC greatly retarded the growth rate of the stems of the plants under both temperature regimes; this effect persisted for about 17 and 24 days under the high and normal temperature regimes, respectively. With plants grown at high temperatures CCC applied at the start of flowering greatly reduced flower shedding and slightly increased the fruit set and fruit development of hand-pollinated flowers. With plants grown at normal temperatures, however, the effects of CCC were slight. CCC-treated plants were sturdy with dark-green leaves which remained green longer, especially under the high temperature regime. More N accumulated in the tissues of plants grown at high temperatures than at normal temperatures, and the N content of the latter plants was considerably increased by CCC treatment. The root development of the CCC-treated plants was much more extensive than that of the untreated plants. The numbers of seeds in the hand-pollinated fruit were not affected by CCC, but at high temperatures there were considerably less seeds than at low temperatures. GA enhanced fruit set of the high-temperature plants, but the fruits were small and seedless. GA also accelerated fruit ripening by 2 and 3 weeks in the plants grown at high and normal temperatures, respectively.-Agric. Univ., Wageningen. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Effect of temperature on a voltage-sensitive electrical synapse in crayfish.

1998 ◽  
Vol 201 (4) ◽  
pp. 503-513 ◽  
Author(s):  
W J Heitler ◽  
D H Edwards
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Input Resistance ◽  
Temperature Limit ◽  
Electrical Synapse ◽  
Membrane Properties ◽  
Effect Of Temperature ◽  
Cold Temperatures ◽  
Q10 Values ◽  
Effective Transmission

The effects of temperature on transmission through the voltage-sensitive giant motor synapse (GMS) were investigated in crayfish both experimentally and in computer simulation. The GMS is part of the fast reflex escape pathway of the crayfish and mediates activation from the lateral giant (LG) command neurone to the motor giant (MoG) flexor motoneurone. The investigation was motivated by an apparent mismatch between the temperature sensitivity of the activation time constant of the GMS, with a Q10 reported to be close to 11, and that of the active membrane properties of LG and MoG, which are thought to have Q10 values close to 3. Our initial hypothesis was that at cold temperatures the very slow activation of the GMS conductance would reduce the effectiveness of transmission compared with higher temperatures. However, the reverse was found to be the case. Effective transmission through the GMS was reliable at low temperatures, but failed at an upper temperature limit that varied between 12 degrees C and 25 degrees C in isolated nerve cord preparations. The upper limit was extended above 30 degrees C in semi-intact preparations where the GMS was less disturbed by dissection. The results of experiments and simulations both indicate that transmission becomes more reliable at low temperatures because the longer-duration presynaptic spikes are able to drive more current through the GMS into the MoG, which is more excitable at low temperatures. Conversely, effective transmission is difficult at high temperatures because the transfer of charge through the GMS is reduced and because the input resistance of MoG is lowered as its current threshold is increased. The effect of the high Q10 of the GMS activation is to help preserve effective transmission through the synapse at high temperatures and so extend the temperature range for effective operation of the escape circuit.

scholarly journals Involvement of Ca2+ in Regulation of Physiological Indices and Heat Shock Factor Expression in Four Iris germanica Cultivars under High-temperature Stress

2014 ◽  
Vol 139 (6) ◽  
pp. 687-698 ◽  
Author(s):  
Jing Mao ◽  
Hongliang Xu ◽  
Caixia Guo ◽  
Jun Tong ◽  
Yanfang Dong ◽  
...  
Keyword(s):  
High Temperature ◽  
Heat Shock ◽  
Temperature Stress ◽  
High Temperatures ◽  
Soluble Protein ◽  
High Temperature Stress ◽  
Temperature Tolerance ◽  
Heat Shock Factor ◽  
High Temperature Tolerance ◽  
Iris Germanica

Although tolerance to high temperature is crucial to the summer survival of Iris germanica cultivars in subtropical areas, few physiological studies have been conducted on this topic previously. To remedy this, this study explored the physiological response and expression of heat shock factor in four I. germanica cultivars with varying levels of thermotolerance. The plants’ respective degrees of high-temperature tolerance were evaluated by measuring the ratio and area of withered leaves under stress. Several physiological responses to high temperatures were investigated, including effects on chlorophyll, antioxidant enzymes, proline, and soluble protein content in the leaves of four cultivars. CaCl2 was sprayed on ‘Gold Boy’ and ‘Royal Crusades’ considered being sensitive to high temperatures to study if Ca2+ could improve the tolerance, and LaCl3 was sprayed on ‘Music Box’ and ‘Galamadrid’ with better high-temperature tolerance to test if calcium ion blocker could decrease their tolerance. Heat shock factor genes were partially cloned according to the conserved region sequence, and expression changes to high-temperature stress with CaCl2 or LaCl3 treatments were thoroughly analyzed. Results showed that high temperature is the primary reason for large areas of leaf withering. The ratio and area of withered leaves on ‘Music Box’ and ‘Galamadrid’ were smaller than ‘Gold Boy’ and ‘Royal Crusades’. CaCl2 slowed the degradation of chlorophyll content and increased proline and soluble protein in ‘Gold Boy’ and ‘Royal Crusades’ but had no significant effect on activating peroxidase or superoxide to improve high-temperature tolerance. Genetic expression of heat shock factor in ‘Gold Boy’ and ‘Royal Crusades’ was upregulated by Ca2+ at later stages of leaf damage under high-temperature stress. LaCl3 down-regulated the physiological parameters and expression level of heat shock factor in ‘Music Box’ and ‘Galamadrid’. These results suggest that different I. germanica cultivars have varying high-temperature tolerance and furthermore that Ca2+ regulates their physiological indicators and expression level of heat shock factor under stress.

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