scholarly journals Low- and High-Temperature Tolerance and Acclimation for Chlorenchyma versus Meristem of the Cultivated Cacti Nopalea cochenillifera, Opuntia robusta, and Selenicereus megalanthus

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Brian R. Zutta ◽  
Park S. Nobel ◽  
Alenoush M. Aramians ◽  
Arineh Sahaghian
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Neutral Red ◽  
Temperature Tolerance ◽  
Temperature Acclimation ◽  
Extreme Temperatures ◽  
Meristematic Cells ◽  
Air Temperatures ◽  
High Temperature Tolerance ◽  
Nopalea Cochenillifera

Dividing meristematic cells are thought to be more sensitive to extreme temperatures compared to other tissues, such as chlorenchyma. This was examined for low and high temperatures for three widely cultivated cacti: Nopalea cochenillifera, Opuntia robusta, and Selenicereus megalanthus. Temperature tolerances of chlorenchyma and meristem were based on the cellular uptake of the vital stain neutral red for plants at mean day/night air temperatures of 25/20°C and plants maintained at 10/5°C or 45/40°C to examine temperature acclimation. Meristematic cells tolerated 1.8°C lower low temperatures and 4.0°C higher high temperatures than chlorenchyma cells for the three species at 25/20°C. Both tissue types showed acclimation, with a decrease or increase in temperature tolerated at 10/5°C or 45/40°C, respectively. Meristematic cells were more tolerant of extreme temperatures compared to chlorenchyma, contrary to the prevailing belief, and may reflect an additional strategy for cacti to survive extreme temperatures.

The Effect of extreme Temperatures on different Stages of Aëdes aegypti (L.)

1957 ◽  
Vol 48 (3) ◽  
pp. 593-599 ◽  
Author(s):  
Micha Bar-Zeev
Keyword(s):  
Aedes Aegypti ◽  
High Temperatures ◽  
Low Temperatures ◽  
Extreme Temperatures ◽  
Fourth Stage ◽  
Wetting And Drying ◽  
The Third ◽  
Adult Females ◽  
Cent Mortality

Earlier investigations of the effects of extreme temperatures on different stages of Aëdes aegypti (L.) were supplemented by studies of eggs, larvae and pupae in water, and of eggs and adult females in air at various relative humidities.Larvae of the same stage, young pupae (defined as those less than half-an-hour old) and old pupae (at least 36 hours old), in groups of 100, 25 and 25, respectively, were kept for various periods at low temperatures in incubators, or, at high temperatures in glass cylinders closed at their lower ends by cloth filters and inserted into water baths, and then transferred to water at 28°C. and the mortality determined from the numbers surviving 24 hr. later (in the case of larvae) or becoming adult (in the case of pupae). Eggs in batches of 1,000 were similarly treated, except that periods of 24 hr. in water at 28°C. with yeast as food added were alternated with 24-hr. periods of drying, and mortality determined on the number that hatched and survived to the third or fourth stage. Adult females (four days old) were exposed in groups of 50 for various periods in jars over appropriate solutions giving a complete range of relative humidities and kept at low, medium and high temperatures. Eggs in batches of 1,000 were subjected to the same treatments. The adults were kept at 28°C. and 60 per cent. R.H. before treatment and for 24 hr. afterwards and mortality then determined. Mortality of eggs was determined after alternate 24-hr. periods of wetting and drying at 28°C., as in the case of eggs treated in water. The results of all the experiments were expressed as the exposure-times required to give 50 per cent. mortality (T50), calculated from the observed data.

Skin folds and Merino breeding. 5. Variations in scrotal, testis, and rectal temperatures as affected by site of measurement, acclimatization to heat and degree of skin fold

1968 ◽  
Vol 8 (31) ◽  
pp. 125 ◽  
Author(s):  
DG Fowler
Keyword(s):  
High Temperatures ◽  
Air Temperature ◽  
Heat Tolerance ◽  
Temperature Regime ◽  
Low Temperatures ◽  
Air Temperatures ◽  
Skin Fold ◽  
Fold Type

In Merino rams, subcutaneous temperature in the scrotum declined from the inguinal border to the distal tip and from posterior to anterior. Testicular temperature was similar at several sites in both testes. Of the total increase in scrotal and testicular temperatures that occurred when rams were heated, the proportional hourly increases were similar at each air temperature above 30�C irrespective of the air temperature regime (stepwise increasing or stepwise decreasing air temperatures) or fold type of the ram. The response of rams depended markedly on the air temperature regime. When air temperatures were decreasing, rams were less able to withstand high temperatures and more able to withstand low temperatures. When air temperatures were increasing the reverse was true. The differences between Folds Plus and Folds Minus rams also depended markedly on the ail temperature regime. In general Folds Minus rams had lower rectal temperatures than Folds Plus rams, but could express their ability to maintain lower subcutaneous scrotal temperatures than Folds Plus rams only after they had gained a degree of acclimatization to heat. Folds Plus rams had higher food intakes than Folds Minus rams which may be a factor in their reduced heat tolerance.

scholarly journals Lethal Effects of High Temperatures on Brown Marmorated Stink Bug Adults before and after Overwintering

Insects ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 355 ◽  
Author(s):  
Davide Scaccini ◽  
Carlo Duso ◽  
Alberto Pozzebon
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Cost Effective ◽  
Temperature Tolerance ◽  
Brown Marmorated Stink Bug ◽  
Stink Bug ◽  
Response Curves ◽  
High Temperature Tolerance ◽  
Before And After ◽  
Temperature Exposure

The invasive brown marmorated stink bug, Halyomorpha halys, is causing economic and ecological damage in invaded areas. Its overwintering behavior warrants mitigation practices in warehouses and shipping operations. The aim of this study was to characterize the mortality response curves of H. halys adults to short high-temperature exposure. Here we compared field-collected individuals entering (ENA) and exiting diapause (EXA). EXA adults displayed increased susceptibility to high temperatures compared to ENA individuals. Complete mortality of all tested individuals was obtained after 10 min exposure at 50.0 °C, and after 15 (EXA) or 20 min (ENA) at 47.5 °C. The nutritional status of these insects had no effect on high-temperature tolerance. The mortality curves obtained here may be used for the definition of cost-effective heat treatments aimed at the H. halys control.

Temperature Tolerance in Young Pacific Salmon, Genus Oncorhynchus

1952 ◽  
Vol 9 (6) ◽  
pp. 265-323 ◽  
Author(s):  
J. R. Brett
Keyword(s):  
High Temperatures ◽  
Low Temperatures ◽  
Oncorhynchus Tshawytscha ◽  
Prolonged Exposure ◽  
Pacific Salmon ◽  
Vertical Gradient ◽  
Temperature Tolerance ◽  
Preferred Temperature ◽  
High And Low Temperatures ◽  
Temperature Responses

Lethal limits of high and low temperatures were determined for the young of five species of Pacific salmon, the spring (Oncorhynchus tshawytscha), the pink (O. gorbuscha), the sockeye (O. nerka), the chum (O. keta) and the coho (O. kisutch).For acclimation temperatures ranging from 5° to 24 °C. significant differences between species in their resistance to high temperatures was obtained. The spring and coho were most resistant. The pink and chum salmon were least resistant, and the sockeye was distinguishable from the latter two by greater resistance for prolonged exposure to high temperatures. No species could tolerate temperatures exceeding 25.1 °C. when exposed for one week.A fanning-out of the opercula was shown to be directly correlated with the onset of death from a low temperature. By use of this criterion mixed lethal effects at low temperatures were demonstrated and found to be influenced by the size of the fish and by the salinity of the water. None of the species could withstand temperatures lower than 4 °C. when acclimated to 20 °C. and above. When taken from holding troughs as low as 5 °C., coho and sockeye could not tolerate long exposure (four days) to 0 °C.In a vertical gradient little difference in preferred temperature was observed, either between species or for different acclimation temperatures. The 12° to 14 °C. stratum was the region of greatest concentration.Specific differences in temperature responses are in keeping with taxonomic and ecological distinctions.

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.

scholarly journals Thermotolerance experiments on active and desiccated states of Ramazzottius varieornatus emphasize that tardigrades are sensitive to high temperatures

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ricardo Cardoso Neves ◽  
Lykke K. B. Hvidepil ◽  
Thomas L. Sørensen-Hygum ◽  
Robyn M. Stuart ◽  
Nadja Møbjerg
Keyword(s):  
High Temperatures ◽  
Temperature Tolerance ◽  
Limiting Factor ◽  
Extreme Conditions ◽  
Upper Limit ◽  
High Temperature Tolerance ◽  
Acclimation Period ◽  
Freshwater Habitats ◽  
Harmful Effects ◽  
Logistic Modelling

AbstractGlobal warming is already having harmful effects on habitats worldwide and it is therefore important to gain an understanding of how rising temperatures may affect extant animals. Here, we investigate the tolerance to high temperatures of Ramazzottius varieornatus, a tardigrade frequently found in transient freshwater habitats. Using logistic modelling on activity we evaluate the effect of 24 hour temperature exposures on active tardigrades, with or without a short acclimation period, compared to exposures of desiccated tardigrades. We estimate that the 50% mortality temperature for non-acclimated active tardigrades is 37.1 °C, with a small but significant increase to 37.6 °C following acclimation. Desiccated specimens tolerate much higher temperatures, with an estimated 50% mortality temperature of 82.7 °C following 1 hour exposures, but with a significant decrease to 63.1 °C following 24 hour exposures. Our results show that metabolically active tardigrades are vulnerable to high temperatures, yet acclimatization could provide a tolerance increase. Desiccated specimens show a much higher resilience—exposure-time is, however, a limiting factor giving tardigrades a restricted window of high temperature tolerance. Tardigrades are renowned for their ability to tolerate extreme conditions, but their endurance towards high temperatures clearly has an upper limit—high temperatures thus seem to be their Achilles heel.

scholarly journals High temperature tolerance in chickpea and its implications for plant improvement

2012 ◽  
Vol 63 (5) ◽  
pp. 419 ◽  
Author(s):  
V. Devasirvatham ◽  
D. K. Y. Tan ◽  
P. M. Gaur ◽  
T. N. Raju ◽  
R. M. Trethowan
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
High Temperatures ◽  
Floral Organ ◽  
Temperature Tolerance ◽  
Male And Female ◽  
High Temperature Tolerance ◽  
The Status ◽  
Significant Yield ◽  
The Impact

Chickpea (Cicer arietinum L.) is an important food legume and heat stress affects chickpea ontogeny over a range of environments. Generally, chickpea adapts to high temperatures through an escape mechanism. However, heat stress during reproductive development can cause significant yield loss. The most important effects on the reproductive phase that affect pod set, seed set and yield are: (1) flowering time, (2) asynchrony of male and female floral organ development, and (3) impairment of male and female floral organs. While this review emphasises the importance of high temperatures >30°C, the temperature range of 32–35°C during flowering also produces distinct effects on grain yield. Recent field screening at ICRISAT have identified several heat-tolerant germplasm, which can be used in breeding programs for improving heat tolerance in chickpea. Research on the impact of heat stress in chickpea is not extensive. This review describes the status of chickpea production, the effects of high temperature on chickpea, and the opportunities for genetic improvement of chickpea tolerance to high temperatures.

scholarly journals Thermal Tolerances of Three Tramp Ant Species (Hymenoptera: Formicidae)

Sociobiology ◽  
2014 ◽  
Vol 59 (1) ◽  
pp. 213 ◽  
Author(s):  
Daniel Russ Solis ◽  
Odair Correa Bueno
Keyword(s):  
Relative Humidity ◽  
High Temperatures ◽  
Low Temperatures ◽  
Abiotic Factors ◽  
Temperature Tolerance ◽  
Urban Habitats ◽  
Monomorium Pharaonis ◽  
Tetramorium Bicarinatum ◽  
Insect Activity ◽  
Tramp Ant

Tramp ant species present a set of adaptations to their urban habitats, and there is a paucity of knowledge about how they interact with abiotic factors, like temperature. Temperature is well known to interfere with insect activity. The present study evaluated the temperature tolerance of three important tramp ant species: Monomorium floricola ( Jerdon), Monomorium pharaonis (Linnaeus) and Tetramorium bicarinatum (Nylander). Tested temperatures were 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48 and 50.C. Ten repetitions with 20 workers each were done with each temperature and analyzed species. The number of dead workers was recorded every hour over a total of 8 hours. All procedures were done using thermal incubators at relative humidity within 50-95%. Workers of M. pharaonis proved more tolerant to high temperatures (30-50.C) than workers of M. floricola and T. bicarinatum. The higher the temperatures tested, greater was the recorded ant mortality, with temperature 50.C being fatal to all species after 1h of exposition. The least tolerant species to temperatures below 20.C was T. bicarinatum. Low temperatures tested were not fatal to any of the tested species.

scholarly journals High-temperature Tolerance of Heritage River Birch Roots Decreased by Pot-In-Pot Production Systems

HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 813-814 ◽  
Author(s):  
John M. Ruter
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Electrolyte Leakage ◽  
Production Systems ◽  
Root Zone ◽  
Root Systems ◽  
Temperature Tolerance ◽  
High Temperature Tolerance ◽  
Aboveground Production ◽  
Membrane Thermostability

Membrane thermostability of Heritage river birch (Betula nigra L. Heritage) was measured by electrolyte leakage from excised roots of plants grown in pot-in-pot (PIP) and conventional aboveground production systems (CPS). The predicted critical midpoint temperature (Tm) for a 30-min exposure was 54.6 ± 0.2 °C for PIP and 56.2 ± 0.6 °C for CPS plants. Plants grown PIP had a steeper slope through the predicted Tm, suggesting a decreased tolerance to high root-zone temperatures in relation to plants grown aboveground. Since the root systems of Heritage river birch grown PIP are damaged at lower temperatures than plants grown aboveground, growers should prevent exposure of root systems to high temperatures during postproduction handling of plants grown PIP.

scholarly journals Tolerance to high temperature in F5 inbred lines of tomato

2014 ◽  
Vol 32 (2) ◽  
pp. 152-158 ◽  
Author(s):  
Lucas S Santos ◽  
Roberto A Melo ◽  
Paulo R Santos ◽  
José LS Carvalho Filho ◽  
Dimas Menezes
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Fruit Set ◽  
Temperature Tolerance ◽  
Fruit Production ◽  
Tomato Mosaic Virus ◽  
High Temperature Tolerance ◽  
Marketable Fruit ◽  
Race 2 ◽  
Lower Luminosity

High temperatures in the growing tomato have caused a reduction in fruit set and consequently productivity. This work aimed to evaluate F5 lines of tomato to fruit set and high temperature tolerance in two culture environments. Two experiments were carried out, one in cultivation in greenhouse and the other in the field conditions, from February to June 2012. We evaluated 20 lines F5 of tomato, originating from the segregation of hybrid SE 1055 F1, developed for the hot and humid conditions, with resistance to Fusarium oxysporum f.sp. lycopersici race 2, the tomato mosaic virus (ToMV), the Verticilium dahliae and geminivirus (TYLCV) and the control cultivar Yoshimatsu and own hybrid SE 1055 F1. The experiment was performed in a randomized blocks design with 22 treatments, four replications and plots with two plants. We evaluated the total number of fruits per plant (NTF/PL), mass of unmarketable fruits per plant (MFNC/PL), fruit set (PEG), mass of marketable fruits per plant (MFC/PL) and yield of marketable fruits (REND). In the greenhouse were recorded higher temperatures and lower luminosity than in field cultivation. Lines 08, 12 and 13 showed higher fruit set in a greenhouse, being more suitable for cultivation at high temperatures. In the field, the lines 06 and 08 showed that marketable fruit production did not differ from 'Yoshimatsu'. Comparing the field experiment average with the average of greenhouse, a higher fruit set and a higher mass of marketable fruits per plant was achieved in field.

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