Saline Growth Conditions Favour Supercooling and Increase the Freezing Tolerance of Leaves of Barley and Wheat

1992 ◽  
Vol 47 (9-10) ◽  
pp. 695-700 ◽  
Author(s):  
Michael Bender ◽  
Ulrich Heber ◽  
Karl-Josef Dietz
Keyword(s):  
Salt Stress ◽  
Freezing Tolerance ◽  
Growth Conditions ◽  
Ice Nucleation ◽  
Ice Formation ◽  
Freezing And Thawing ◽  
Subzero Temperatures ◽  
Cellular Dehydration ◽  
Detached Leaves ◽  
Leaf Survival

When young plants of barley and wheat grown in hydroponic culture were subjected to salt stress, their freezing tolerance increased with increasing severity of salt stress. Detached leaves from salt-stressed plants also exhibited an increased ability to supercool. Avoidance of ice formation permitted leaf survival at subzero temperatures which were no longer tolerated when ice nucleation resulted in extracellular freezing. The increased freezing tolerance under salt stress is attributed to osmotic adjustment of the plants. Increased cellular solute concentrations decrease the extent of cellular dehydration at freezing temperatures, thereby decreasing mechanical and chemical stresses on biomembranes during freezing and thawing.

scholarly journals Freezing Tolerance of Avocado Leaves

HortScience ◽  
1992 ◽  
Vol 27 (4) ◽  
pp. 341-343 ◽  
Author(s):  
M.A. McKellar ◽  
D.W. Buchanan ◽  
Dewayne L. Ingram ◽  
C.W. Campbell
Keyword(s):  
Freezing Tolerance ◽  
Leaf Tissue ◽  
Freezing Temperature ◽  
Temperature Limit ◽  
Persea Americana ◽  
Ice Formation ◽  
Visual Appearance ◽  
Detached Leaves ◽  
Time Of Year ◽  
Lower Temperature

Freezing tolerance and the lethal freezing temperature were determined for detached leaves of avocado (Persea americana Mill.) by either electrolyte leakage or visual appearance of browning. Leaves from field-grown trees of `Gainesville', `Booth8', and `Winter Mexican' in both Gainesville and Homestead, Fla., were evaluated. All cultivars in both locations survived ice formation in their tissue. Leaf tissue had a temperature limit (lethal freeze temperature) at and below which the tissue died. The lethal freezing temperature varied from -5.1 to -9.3C, depending on time of year and location. The lethal freeze temperature for a cultivar decreased over the fall and winter as temperatures decreased. Leaves of `Booth-8' and Winter Mexican' decreased 2.5 and 1.5C, respectively, in Homestead from 13 Nov. 1982 to 5 Feb. 1983. The plants growing at the lower temperature location (Gainesville) had lower lethal freeze temperatures. Leaves of `Gainesville' had a lethal freeze temperature of - 9.3C from trees at Gainesville and - 7.8C from trees at Homestead.

scholarly journals Role of Ice Nucleation and Antifreeze Activities in Pathogenesis and Growth of Snow Molds

2000 ◽  
Vol 90 (4) ◽  
pp. 354-361 ◽  
Author(s):  
Christopher S. Snider ◽  
Tom Hsiang ◽  
Guiying Zhao ◽  
Marilyn Griffith
Keyword(s):  
Low Temperature ◽  
Host Plants ◽  
Ice Nucleation ◽  
Microdochium Nivale ◽  
Ice Formation ◽  
Subzero Temperatures ◽  
Nucleation Activity ◽  
Ice Nucleation Activity ◽  
Antifreeze Activity

We examined the ability of snow molds to grow at temperatures from -5 to 30°C and to influence the growth of ice through assays for ice nucleation and antifreeze activities. Isolates of Coprinus psychromorbidus (low temperature basidiomycete variant), Microdochium nivale, Typhula phacorrhiza, T. ishikariensis, T. incarnata, and T. canadensis all grew at -5°C, whereas Sclerotinia borealis and S. homoeocarpa did not grow at temperatures below 4°C. The highest threshold ice nucleation temperature was -7°C. Because snow molds are most damaging to their hosts at temperatures above this, our results imply that the pathogenesis of these fungi is not dependent on ice nucleation activity to cause freeze-wounding of host plants. All snow molds that grew at subzero temperatures also exhibited antifreeze activity in the growth medium and in the soluble and insoluble hyphal fractions, with the exception of M. nivale and one isolate of T. canadensis. The lack of high ice nucleation activity combined with the presence of antifreeze activity in all fungal fractions indicates that snow molds can moderate their environment to inhibit or modify intra- and extracellular ice formation, which helps explain their ability to grow at subzero temperatures under snow cover.

scholarly journals Cold-Tolerance Mechanisms of the Antarctic Nematode Panagrolaimus Davidi

1991 ◽  
Vol 155 (1) ◽  
pp. 629-641
Author(s):  
D. A. WHARTON ◽  
I. M. BROWN
Keyword(s):  
Surface Water ◽  
Relative Humidity ◽  
Freezing Tolerance ◽  
Thermal History ◽  
Liquid Paraffin ◽  
Ice Nucleation ◽  
Ice Formation ◽  
Tolerance Mechanisms ◽  
The Antarctic

When free of surface water in air or liquid paraffin, the antarctic nematode Panagrolaimus davidi is freezing intolerant but avoids freezing by supercooling. Survival of long-term exposure is enhanced by sub-zero temperatures compared with controls maintained at 99% relative humidity and 15°C. In water the nematodes are seeded by exogenous ice nucleation and a proportion are freezing tolerant. Ice formation appears to be restricted to the pseudocbel. The degree of freezing tolerance is dependent upon the age of the culture and its thermal history. P. davidi is freezing tolerant when exposed to sub-zero temperatures in water and freezing intolerant when free of surface water and able to supercool. These two strategies are not mutually exclusive as they are often thought to be in arthropods.

scholarly journals Method for maintenance of coffee leaves in vitro for mass rearing of Leucoptera coffeellum (Guérin-Méneville) (Lepidoptera: Lyonetiidae)

2000 ◽  
Vol 29 (4) ◽  
pp. 849-854 ◽  
Author(s):  
Ronaldo Reis Jr. ◽  
Lima ◽  
Evaldo F. Vilela ◽  
Raimundo S. Barros
Keyword(s):  
Plant Growth ◽  
Mass Rearing ◽  
Developmental Cycle ◽  
Plant Tissues ◽  
Distilled Water ◽  
Complete Development ◽  
Detached Leaves ◽  
Leaf Survival ◽  
The Ideal

To accomplish systematic studies with coffee leafminer, it is necessary to establish a mass rearing system under artificial conditions. It is possible to rear this species, from egg to adult, under laboratory conditions, without using coffee seedlings but detached leaves maintained in vitro. Synthetic cytokinins are routinely used for maintenance of plant cell and plant tissues in vitro. Two plant growth regulators, benzyladenin and kinetin, in concentrations 10-6 and 10-7 M were used to mantain the leaves. Green leaves collected in the field were maintained in the solution to be tested. Distilled water served as control. The experiment lasted 30 days, a period longer than the necessary for the complete development of the insect. Both artificial cytokinines indeed increased the lifetime of the coffee leaves, maintaining them green and healthy. Leaves placed in the cages for oviposition were attractive to the insect, with significant number of eggs per leaf. In most cases, eggs resulted in individuals that completed the whole developmental cycle. Tests with regulator in different concentrations with healthy leaves showed efficiency. However, we believe that hormone concentrations to be used with mined leaves should be larger, because these when maintained at 10-7 M leaves did not present a satisfactory lifetime. Therefore, tests with mined leaves with different hormone concentrations should be made to find out the ideal concentration for leaf survival. In our laboratory we are successfully using 10-6 M benzyladenin for the maintenance of mined leaves.

scholarly journals Identification of Key Genes in ‘Luang Pratahn’, Thai Salt-Tolerant Rice, Based on Time-Course Data and Weighted Co-expression Networks

2021 ◽  
Vol 12 ◽  
Author(s):  
Pajaree Sonsungsan ◽  
Pheerawat Chantanakool ◽  
Apichat Suratanee ◽  
Teerapong Buaboocha ◽  
Luca Comai ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Stress Responses ◽  
Time Course ◽  
Rice Variety ◽  
Enrichment Analysis ◽  
Normal Growth ◽  
Growth Conditions ◽  
Pathway Enrichment Analysis ◽  
Key Genes

Salinity is an important environmental factor causing a negative effect on rice production. To prevent salinity effects on rice yields, genetic diversity concerning salt tolerance must be evaluated. In this study, we investigated the salinity responses of rice (Oryza sativa) to determine the critical genes. The transcriptomes of ‘Luang Pratahn’ rice, a local Thai rice variety with high salt tolerance, were used as a model for analyzing and identifying the key genes responsible for salt-stress tolerance. Based on 3' Tag-Seq data from the time course of salt-stress treatment, weighted gene co-expression network analysis was used to identify key genes in gene modules. We obtained 1,386 significantly differentially expressed genes in eight modules. Among them, six modules indicated a significant correlation within 6, 12, or 48h after salt stress. Functional and pathway enrichment analysis was performed on the co-expressed genes of interesting modules to reveal which genes were mainly enriched within important functions for salt-stress responses. To identify the key genes in salt-stress responses, we considered the two-state co-expression networks, normal growth conditions, and salt stress to investigate which genes were less important in a normal situation but gained more impact under stress. We identified key genes for the response to biotic and abiotic stimuli and tolerance to salt stress. Thus, these novel genes may play important roles in salinity tolerance and serve as potential biomarkers to improve salt tolerance cultivars.

Possible mechanisms of protection against freezing and thawing damage by subzero temperatures

Cryobiology ◽  
1974 ◽  
Vol 11 (6) ◽  
pp. 548 ◽  
Author(s):  
J. Farrant ◽  
L.E. McGann ◽  
Stella C. Knight
Keyword(s):  
Freezing And Thawing ◽  
Subzero Temperatures

scholarly journals Overexpression of WAX INDUCER1/SHINE1 Gene Enhances Wax Accumulation under Osmotic Stress and Oil Synthesis in Brassica napus

2019 ◽  
Vol 20 (18) ◽  
pp. 4435 ◽  
Author(s):  
Ning Liu ◽  
Jie Chen ◽  
Tiehu Wang ◽  
Qing Li ◽  
Pengpeng Cui ◽  
...  
Keyword(s):  
Salt Stress ◽  
Brassica Napus ◽  
De Novo ◽  
Normal Growth ◽  
Acid Synthesis ◽  
Growth Conditions ◽  
Lipid Profiling ◽  
Intracellular Lipids ◽  
Oil Synthesis ◽  
Genes Encoding

WAX INDUCER1/SHINE1 (WIN1) belongs to the AP2/EREBP transcription factor family and plays an important role in wax and cutin accumulation in plants. Here we show that BnWIN1 from Brassica napus (Bn) has dual functions in wax accumulation and oil synthesis. Overexpression (OE) of BnWIN1 led to enhanced wax accumulation and promoted growth without adverse effects on oil synthesis under salt stress conditions. Lipid profiling revealed that BnWIN1-OE plants accumulated more waxes with elevated C29-alkanes, C31-alkanes, C28-alcohol, and C29-alcohol relative to wild type (WT) under salt stress. Moreover, overexpression of BnWIN1 also increased seed oil content under normal growth conditions. BnWIN1 directly bound to the promoter region of genes encoding biotin carboxyl carrier protein 1 (BCCP1), glycerol-3-phosphate acyltransferase 9 (GPAT9), lysophosphatidic acid acyltransferase 5 (LPAT5), and diacylglycerol acyltransferase 2 (DGAT2) involved in the lipid anabolic process. Overexpression of BnWIN1 resulted in upregulated expression of numerous genes involved in de novo fatty acid synthesis, wax accumulation, and oil production. The results suggest that BnWIN1 is a transcriptional activator to regulate the biosynthesis of both extracellular and intracellular lipids.

Ice Formation as an Indicator of Frost-Resistance on the Concrete Containing Slag Cement in Conditions of Freezing and Thawing

2016 ◽  
Vol 865 ◽  
pp. 145-150
Author(s):  
Oleksandr Moskalenko ◽  
Rayisa Runova
Keyword(s):  
Frost Resistance ◽  
Ice Formation ◽  
Cement Concrete ◽  
Chemical Additives ◽  
Freezing And Thawing ◽  
Slag Cement ◽  
Mineral Supplement

The connection with the icing on the frost resistance of concrete containing slag cement and chemical additives «MC Bauchemie» under freezing and thawing.It is shown that freeze concrete samples at (-) 10°C increase in the amount of slag from 30 to 70 wt.% Of binder in the composition leads to an increase in the index of ice formation in the concrete of 1.7 ... 1.9 times compared with the concrete obtained at a slag containing slag cement with a content of 10 wt.%. Frost resistance of concrete is reduce from F450 to F400.When freezing of concrete samples at (-) 20°C increase in the amount of slag from 30 to 50 wt. % Binder in the composition leads to an increase in the index of ice formation in the concrete of 1.7 times compared with the concrete obtained on slag cement containing slag with a content of 10 wt.%. Frost resistance of concrete is reduce from F400 to F350.The concrete on the slag containing cement with slag 70 wt. % is observed a slight decrease in ice formation. However, its value is 1.4 times higher than ice formation in concretes containing slag in an amount of 10 wt. %. Mark on frost resistance remains at F350.The smallest ice formation, regardless of the content of the slag into the slag containing cement, concrete characterized in that use complex organo-mineral supplement SX (5%) + SP (0.6%) in the amount of 5.6%. According to the degree of influence of additives used to reduce ice formation in the slag in concretes, containing cements can be ranker number: SX (5%) + SP (0.6%) > NC (5%) + SP (0.6%) > SP (0.6%).

scholarly journals Enhanced ice nucleation activity of coal fly ash aerosol particles initiated by ice-filled pores

2019 ◽  
Author(s):  
Nsikanabasi Silas Umo ◽  
Robert Wagner ◽  
Romy Ullrich ◽  
Alexei Kiselev ◽  
Harald Saathoff ◽  
...  
Keyword(s):  
Fly Ash ◽  
Significant Role ◽  
Coal Fly Ash ◽  
Aerosol Particles ◽  
Ice Nucleation ◽  
Temperature Cycling ◽  
Cloud Formation ◽  
Ice Formation ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Ice-nucleating particles (INPs), which are precursors for ice formation in clouds, can alter the microphysical and optical properties of clouds, hence, impacting the cloud lifetimes and hydrological cycles. However, the mechanisms with which these INPs nucleate ice when exposed to different atmospheric conditions are still unclear for some particles. Recently, some INPs with pores or permanent surface defects of regular or irregular geometries have been reported to initiate ice formation at cirrus temperatures via the liquid phase in a two-step process, involving the condensation and freezing of supercooled water inside these pores. This mechanism has therefore been labelled as pore condensation and freezing (PCF). The PCF mechanism allows formation and stabilization of ice germs in the particle without the formation of macroscopic ice. Coal fly ash (CFA) aerosol particles are known to nucleate ice in the immersion freezing mode and may play a significant role in cloud formation. In our current ice nucleation experiments with CFA particles, which we conducted in the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) aerosol and cloud simulation chamber at the Karlsruhe Institute of Technology, Germany, we partly observed a strong increase in the ice-active fraction for experiments performed at temperatures just below the homogeneous freezing of pure water, which could be related to the PCF mechanism. To further investigate the potential of CFA particles undergoing PCF mechanism, we performed a series of temperature-cycling experiments in AIDA. The temperature-cycling experiments involve exposing CFA particles to lower temperatures (down to ~ 228 K), then warming them up to higher temperatures (238 K–273 K) before investigating their ice nucleation properties. For the first time, we report the enhancement of the ice nucleation activity of the CFA particles for temperatures up to 263 K, from which we conclude that it is most likely due to the PCF mechanism. This indicates that ice germs formed in the CFA particles’ pores during cooling remains in the pores during the warming and induces ice crystallization as soon as the pre-activated particles experience ice-supersaturated conditions at warmer temperatures; hence, showing an enhancement in their ice-nucleating ability compared to the scenario where the CFA particles are directly probed at warmer temperatures without temporary cooling. The enhancement in the ice nucleation ability showed a positive correlation with the specific surface area and porosity of the particles. On the one hand, the PCF mechanism could be the prevalent nucleation mode for intrinsic ice formation at cirrus temperatures rather than the previously acclaimed deposition mode. On the other, the PCF mechanism can also play a significant role in mixed-phase cloud formation in a case where the CFA particles are injected from higher altitudes and then transported to lower altitudes after being exposed to lower temperatures.

Fish Antifreeze Proteins: Recent Gene Evolution

1986 ◽  
Vol 43 (5) ◽  
pp. 1028-1034 ◽  
Author(s):  
Gary K. Scott ◽  
Garth L. Fletcher ◽  
Peter L. Davies
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Genomic Organization ◽  
Gene Evolution ◽  
Antifreeze Proteins ◽  
Gene Organization ◽  
Ice Formation ◽  
Polar Regions ◽  
Subzero Temperatures ◽  
Combining Evidence

A variety of antifreeze proteins is produced by marine teleosts inhabiting polar regions to ensure protection from internal ice formation at subzero temperatures. Combining evidence from paleoclimatology, teleostian evolution, and studies of antifreeze gene organization, the case is made for Cenozoic cooling as the force driving antifreeze evolution in marine teleosts. The distribution of antifreeze types amongst teleost suborders, families, genera, and species correlates with Cenozoic glaciation in the Southern Hemisphere preceding that in the Northern Hemisphere by approximately 25 million yr. The genomic organization of antifreeze genes suggests recent and extensive amplification, an event compatible with their proposed stress-induced origin. Also, a realignment of the nototheniids with the Gadiformes based on antifreeze protein data is suggested.

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