Effects of low temperature on leaf diffusion resistance of Ulmus americana and Fraxinus pennsylvanica seedlings

1979 ◽  
Vol 57 (21) ◽  
pp. 2466-2470 ◽  
Author(s):  
T. T. Kozlowski ◽  
S. G. Pallardy
Keyword(s):  
Low Temperature ◽  
Cold Stress ◽  
Low Temperatures ◽  
Stomatal Closure ◽  
Diffusion Resistance ◽  
Fraxinus Pennsylvanica ◽  
Ulmus Americana ◽  
Stress Treatment ◽  
Exposure To Cold

Low temperatures (3–10 °C) for 1 h to 6 days increased leaf diffusion resistance (r1) of Ulmus americana and Fraxinus pennsylvanica seedlings, indicating rapid stomatal closure. The change in r1 increased as the temperature was lowered over a range of 10–3 °C. After cessation of cold-stress treatment, r1 values recovered within 1 day to prestress levels. No significant differences were found in speed of recovery of r1 in plants after exposure to cold over a range of 3– 10 °C. Stomatal closure could account thus for at least part of the decrease in photosynthesis at low temperatures.

INVESTIGATIONS OF PERMEABILITY, DIAPAUSE, AND HATCHING IN THE EGGS OF THE MOSQUITO AEDES HEXODONTUS DYAR

1958 ◽  
Vol 36 (4) ◽  
pp. 541-554 ◽  
Author(s):  
W. E. Beckel
Keyword(s):  
Low Temperature ◽  
Sodium Hypochlorite ◽  
Water Loss ◽  
Low Temperatures ◽  
Room Temperature ◽  
Early Embryo ◽  
Adult Mosquito ◽  
Egg Cell ◽  
Distilled Water ◽  
Exposure To Cold

Methods for collection in the laboratory of many thousands of eggs from field-collected, blood-fed females are described. Also a way of separating fertile from infertile eggs is outlined. When the eggs are laid they are white but begin to darken within one-half hour. The darkening did not occur when the egg cell or early embryo was killed.Two changes in permeability in the prediapause stage of the eggs of Aedcs hexodontus were observed. The first took place as the chorion changed from white to black. The egg lost and gained water easily when first laid but resisted water loss and uptake as the chorion darkened. However, a complete waterproofing did not result. With the formation of the transparent cuticle a further change in permeability occurred. The egg lost hardly any water even when exposed to extreme desiccation and what little water was lost was regained very slowly. However, the cuticle, with the chorion removed in sodium hypochlorite, was quite permeable. The impermeability of the chorion and cuticle combination must result from the bonding between the two and this bonding must be disrupted by the dechorionation.To study the obligate diapause that occurs in the late embryogeny of the mosquito egg the effect of making water available to the embryo, of light, and of low temperature was studied. Diapause was not broken when water was available to the embryo, nor did alternate periods of light and dark at room temperature or at lower temperatures disrupt the diapause. To test the influence of cold the temperature of 1° and −3 °C. were used to simulate the temperatures in the field. The low temperatures were found to terminate the diapause but the numbers of eggs hatching did not steadily increase with an increase in the time of exposure to cold. No clue has as yet been discovered to explain these results. A hatching infusion of decaying adult mosquito bodies in distilled water was found to give more hatching than did distilled water alone. The mechanism of the hatching stimulus is not known.

Light Intensity: the Role Player in Cucumber Response to Cold Stress

2021 ◽  
Author(s):  
Tahereh Ashrestaghi ◽  
Sasan Aliniaeifard ◽  
Aida Shomali ◽  
Shiva Azizinia ◽  
Jahangir Abbasi Koohpalekani ◽  
...  
Keyword(s):  
Low Temperature ◽  
Light Intensity ◽  
Cold Stress ◽  
Low Temperatures ◽  
Warm Season ◽  
Water Soluble ◽  
Photon Flux ◽  
Soluble Carbohydrate ◽  
Dependent Manner ◽  
Biochemical Traits

Abstract Low temperatures are an important limitation for geographic distributions of warm-season crops like cucumber (Cucumis sativus L.). Tolerance to low temperatures varies among different plant species and genotypes when changes in normal environmental cues occur. To cope with low temperature, biochemical and biophysical events should be coordinated to form a physiological response. We examined how light intensity influences the effects of low temperature on photosynthesis machinery and some biochemical traits. We used chlorophyll fluorescence imaging and polyphasic fluorescence transient (OJIP) to analyze cold stress (4 ºC) damage to photosynthetic electron transport chain (ETC) under different Photosynthetic Photon Flux Densities (PPFDs; 0, 300 and 600 μmol m-2 s-1), in four accessions of cucumber. The results showed that, the negative effects of cold stress are PPFD-dependent. The adverse effect of cold stress on ETC was more pronounced in plants exposed to 600 μmol m-2 s-1 compared to the control and dark-exposed plants; indicated by disturbance in ETC and higher energy dissipation. Moreover, biochemical traits including H2O2 content, ascorbate peroxidase activity and electrolyte leakage, and water-soluble carbohydrate was increased under low temperature by increase in PPFD, while chlorophyll and carotenoid contents decreased under low temperature by PPFD elevation. Low temperature induced H2O2 accumulation via suppressing APX activity in a PPFD-dependent manner. In conclusion, high PPFDs exacerbate the adverse effects of low temperature on the cucumber seedlings.

scholarly journals The Effect of Cold Stress on Damping-Off of Soybean Caused by Pythium sylvaticum

Plant Disease ◽  
2018 ◽  
Vol 102 (11) ◽  
pp. 2194-2200 ◽  
Author(s):  
M. Serrano ◽  
A. E. Robertson
Keyword(s):  
Cold Stress ◽  
Seedling Growth ◽  
Low Temperatures ◽  
Mycelial Growth ◽  
Factorial Experiment ◽  
Damping Off ◽  
Exposure To Cold ◽  
Pythium Sylvaticum ◽  
Increased Susceptibility

To improve our understanding of the timing of cold stress and its effect on Pythium damping-off, we performed a factorial experiment with two cold stress temperatures (4 and 10°C); exposure to 96 h of cold stress at 0, 1, 2, 4, 6, and 8 days after planting; and inoculation with Pythium sylvaticum-infested millet or control. Increased susceptibility to damping-off resulting in reduced emergence was found in inoculated plants when the cold stress period began 2 or 4 days after planting. In the noninoculated controls, no effect of cold stress on emergence was observed. Slower seedling growth was observed during the cold stress period and in inoculated plants after exposure to cold stress. Seed exudation, mycelial growth, and sporangia germination of P. sylvaticum was evaluated at 4, 10, and 18°C. The greatest seed exudation was observed at 4°C. Low temperatures delayed mycelial growth of P. sylvaticum, although the pathogen was still able to grow at 4°C. Sporangia incubated for 3 h at 18°C in the presence of seed exudates had higher germination in comparison with sporangia incubated at 10 or 4°C. Moreover, more sporangia germinated in response to seed exudates that were previously collected from seed imbibed for 24 h at low temperatures (4°C). These results suggest that cold stress 2 to 4 days after planting increases soybean susceptibility to damping-off, presumably because of increased seed exudation and delayed seedling growth.

scholarly journals Light Intensity: The Role Player in Cucumber Response to Cold Stress

Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 201
Author(s):  
Tahereh Ashrostaghi ◽  
Sasan Aliniaeifard ◽  
Aida Shomali ◽  
Shiva Azizinia ◽  
Jahangir Abbasi Koohpalekani ◽  
...  
Keyword(s):  
Electron Transport ◽  
Low Temperature ◽  
Light Intensity ◽  
Cold Stress ◽  
Ascorbate Peroxidase ◽  
Peroxidase Activity ◽  
Low Temperatures ◽  
Electron Transport Chain ◽  
Biochemical Traits ◽  
Transport Chain

Low temperatures are a substantial limitation in the geographic distribution of warm-season crops such as cucumber (Cucumis sativus L.). Tolerance to low temperatures varies among different plant species and genotypes when changes in environmental cues occur. Therefore, biochemical and biophysical events should be coordinated to form a physiological response and cope with low temperatures. We examined how light intensity influences the effects of low temperature on photosynthesis and some biochemical traits. We used chlorophyll fluorescence imaging and polyphasic fluorescence transient to analyze cold stress damage by 4 °C. Photosynthetic Photon Flux Densities (PPFDs) of 0, 300, and 600 μmol m−2 s−1, in four accessions of cucumber, were investigated. The results show that the negative effects of cold stress are PPFD-dependent. The adverse effect of cold stress on the electron transport chain is more pronounced in plants exposed to 600 μmol m−2 s−1 than the control and dark-exposed plants, indicated by a disturbance in the electron transport chain and higher energy dissipation. Moreover, biochemical traits, including the H2O2 content, ascorbate peroxidase activity, electrolyte leakage, and water-soluble carbohydrate, increased under low temperature by increasing the PPFD. In contrast, chlorophyll and carotenoid contents decreased under low temperature through PPFD elevation. Low temperature induced a H2O2 accumulation via suppressing ascorbate peroxidase activity in a PPFD-dependent manner. In conclusion, high PPFDs exacerbate the adverse effects of low temperature on the cucumber seedlings.

A Study of Arabidopsis Cold Stress Tolerance Improvement via AthHOS1-Targeting HOS1-AmiRNA Approach

2021 ◽  
Author(s):  
Marzieh Karimi ◽  
Behrouz Shiran ◽  
Mohammad Rabei ◽  
Hossein Fallahi ◽  
Bojana Banović Đeri
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Circadian Rhythm ◽  
Comparative Analysis ◽  
Low Temperature ◽  
Transgenic Plants ◽  
Cold Stress ◽  
Stress Tolerance ◽  
Low Temperatures ◽  
Wild Type

Abstract In this study the artificial microRNAs (amiRNAs) technology targeting HOS1 gene was tested for its applicability for the improvement of cold stress tolerance in Landsberg-0 (Ler-0) ecotype of Arabidopsis thaliana. The chosen approach was designed to suppress AtHOS1 gene expression through the overexpression of amiRNA-HOS1. The effect of AtHOS1-amiRNA overexpression to transgenic plants’ response to cold stress was determined by Real Time PCR. The expression levels of amiRNA and its target, AtHOS1 gene, were observed in 3-week old seedlings of T3 generation and in wild-type plants after 6h, 12h, 24h, 48h and 96h of their exposure to cold stress (4ºC). Comparative analysis revealed that AtHOS1-amiRNA negatively regulated AtHOS1 in transgenic plants upon plants lengthen exposure (for 48h and 96h) to low temperature (Pearson’s correlation coefficient of -0.407; P < 0.05). Even though prolonged cold stress caused extended up regulation of AtHOS1 in wild type plants, in transgenic plants AtHOS1-amiRNA suppression disturbed expected AtHOS1 circadian rhythm by preventing further AtHOS1 up regulation. Moreover, transgenic plants showed AtHOS1 down regulation 96h after the cold stress onset, due to sufficient overexpression of AtHOS1-amiRNA, which allowed cold signaling amplification in transgenic plants. As a result of that, cold-acclimated transformed plants displayed 17% higher freezing tolerance (-1°C to -8°C) in comparison to wild type plants, demonstrating the success of chosen approach in improving Arabidopsis tolerance to low temperatures, at least in Ler-0 ecotype.

scholarly journals Effect of low temperature in the first development stage for five red raspberry genotypes

2019 ◽  
Vol 46 (No. 1) ◽  
pp. 9-16
Author(s):  
Elida Contreras ◽  
Javiera Grez ◽  
José A Alcalde ◽  
Davide Neri ◽  
Marina Gardella
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Development Stage ◽  
Red Raspberry ◽  
Stages Of Development ◽  
Growth Season ◽  
Early Stages ◽  
Exposure To Cold ◽  
Moment Interaction ◽  
Cold Chamber

In raspberry, the expression of the primocane fruiting trait is influenced by the environment. Although there are several factors that influence the expression of this character, it is well known that low temperatures that occur during the growth season of the primocane, are important and affect the flowering. In this study, plants in their early stages of development were exposed to low temperatures (2°C) for one month, in a dark cold chamber. The following genotypes primocane and floricane were used: ‘UC103’, ‘Autumn Bliss’, ‘Heritage’, ‘Meeker’ and ‘Tulameen’. Flowering and growth were recorded until the end of the season and the morphology of the meristem was characterized in this moment. Interaction between cold and genotype was detected in all parameters studied. In ‘Heritage’, a slight primocane, growth and flowering were favoured by exposure to cold. Thereby, low temperature affects flowering, but this effect depends on primocane fruiting degree of each genotype, slight primocane the cold favored flowering and growth. However, strongly primocane the cold had no effect on flowering and growth.

Eosinophil Levels of the Turtle After Exposure to Cold and Epinephrine

1957 ◽  
Vol 188 (2) ◽  
pp. 420-422 ◽  
Author(s):  
Richard St. John ◽  
Roland M. Nardone
Keyword(s):  
Low Temperature ◽  
Cold Stress ◽  
Cold Exposure ◽  
Combined Treatment ◽  
Control Level ◽  
Endocrine Response ◽  
Epinephrine Injection ◽  
Exposure To Cold ◽  
Temperature Environment ◽  
Average Rise

The effect of cold exposure, epinephrine injection, and a combined cold-epinephrine treatment on the eosinophil level of the turtle, Pseudemys elegans, was studied in order to ascertain information regarding the sensitivity of the endocrine and nervous systems of a poikilotherm to stresses. A low temperature environment produced an eosinopenia; the average fall was 34.8% below the control level. Epinephrine injection resulted in an eosinophilia; the average rise was 37.4% above the control level. Combined treatment with cold and epinephrine resulted in an eosinopenia; the average fall was 32.8% below the control level. It is concluded that the turtle shows an endocrine response to cold stress.

In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

1975 ◽  
Vol 33 ◽  
pp. 58-59
Author(s):  
F. H. Louchet ◽  
L. P. Kubin
Keyword(s):  
Electron Microscope ◽  
Transition Temperature ◽  
Low Temperature ◽  
Slip System ◽  
Low Temperatures ◽  
Tensile Axis ◽  
Image Intensifier ◽  
Screw Dislocations ◽  
Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

INVAR M93

Alloy Digest ◽  
2008 ◽  
Vol 57 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Low Temperatures ◽  
Bend Strength ◽  
Temperature Performance ◽  
Ni Content ◽  
Precision Alloys ◽  
Ni Alloy

Abstract Invar is an Fe-Ni alloy with 36% Ni content that exhibits the lowest expansion of known metals from very low temperatures up to approximately 230 deg C (445 deg F). Invar M93 is a cryogenic Invar with improved weldability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear and bend strength as well as fracture toughness and fatigue. It also includes information on low temperature performance as well as forming and joining. Filing Code: FE-143. Producer or source: Metalimphy Precision Alloys.

FEC-LiTFSI-Pyr1ATFSI Ionic Liquid Electrolyte to Improve Low Temperature Performance of Lithium-Ion Batteries

2014 ◽  
Vol 986-987 ◽  
pp. 80-83
Author(s):  
Xiao Xue Zhang ◽  
Zhen Feng Wang ◽  
Cui Hua Li ◽  
Jian Hong Liu ◽  
Qian Ling Zhang
Keyword(s):  
Low Temperature ◽  
Lithium Ion Batteries ◽  
Low Temperatures ◽  
Freezing Point ◽  
Lithium Ion ◽  
Liquid Electrolyte ◽  
Capacity Retention ◽  
Composite Electrolyte ◽  
Ionic Liquid Electrolyte ◽  
Fluoroethylene Carbonate

N-methyl-N-allylpyrrolidinium bis (trifluoromethanesulfonyl) imide (PYR1ATFSI) with substantial supercooling behavior is synthesized to develop low temperature electrolyte for lithium-ion batteries. Additive fluoroethylene carbonate (FEC) in LiTFSI/PYR1ATFSI/EC/PC/EMC is found that it can reduce the freezing point. LiFePO4/Li coin cells with the FEC-PYR1ATFSI electrolyte exhibit good capacity retention, reversible cycling behavior at low temperatures. The good performance can be attributed to the decrease in the freezing point and the polarization of the composite electrolyte.

Sign in / Sign up

Export Citation Format

Share Document