Stand establishment in processing carrots – Effects of various temperature regimes on germination and the role of salicylates in promoting germination at low temperatures

2002 ◽  
Vol 82 (2) ◽  
pp. 443-450 ◽  
Author(s):  
Lada R. Rajasekaran ◽  
Azure Stiles, Claude ◽  
D. Caldwell
Keyword(s):  
Low Temperature ◽  
Acetylsalicylic Acid ◽  
Low Temperatures ◽  
Seed Treatment ◽  
Germination Percentage ◽  
Threshold Temperature ◽  
Critical Threshold ◽  
Temperature Regimes ◽  
Carrot Seed

The effects of various temperature regimes on carrot seed germination and the possibility of hastening germination at a low temperature using salicylates were studied. Seeds were incubated at various temperatures viz., 25, 20, 15, 10, 5 and 2°C. Salicylates such as, 2,6-dihydoxybenzoic acid (DHBA), acetylsalicylic acid (ASA), salicylic acid (SA) were supplied at 0, 1, 10, 100 and 1000 mg L-1 continually to the seeds incubated at 25 and 5°C until germination. Data on germination percentage were collected, and vigor value was calculated. Incubating seeds at various low temperature regimes significantly and proportionately reduced germination percentage and vigor value. The highest cumulative germination and vigor value was observed at 25°C. Critical threshold temperature for germination (GT50) was 5°C. Seed treatment using salicylates hastened germination at 5°C. 2,6-dihydoxybenzoic acid 1, ASA 100 and SA 1 mg L-1 all were effective in hastening germination at 5°C. Among all the salicylates, ASA 100 mg L-1 was the most effective in advancing germination at 5°C. Salicylates at the highest concentration of 1000 mg L-1 inhibited germination significantly both at 25 and 5°C. Key words: Acetylsalicylic acid, carrot, 2,6-dihydoxybenzoic acid, germination percentage, rate of germination, salicylates, SA, temperature, thermogenesis, vigor value

The effect of temperature on cold hardening of Loliutn perenne seedlings

1980 ◽  
Vol 95 (1) ◽  
pp. 77-81 ◽  
Author(s):  
M. P. Fuller ◽  
C. F. Eagles
Keyword(s):  
Lolium Perenne ◽  
Low Temperatures ◽  
Cold Hardiness ◽  
Leaf Growth ◽  
Effect Of Temperature ◽  
Threshold Temperature ◽  
Screening Techniques ◽  
Temperature Regimes ◽  
Different Temperatures ◽  
Cool Night

SummaryThe variation in hardening responses under different temperature regimes for three cultivars of Lolium perenne L. is described. The relative cold hardiness of the cultivars was modified by different temperatures during hardening. A threshold temperature existed above which hardening did not occur, but this temperature varied between cultivars.Although continuous low temperatures (2 °C) favoured hardening, hardening also occurred under warm day and cool night conditions (15:2 °C) where cultivars showed contrasting hardiness responses in daylengths of 16, 12 and 8 h. Under some of these conditions both leaf growth and hardiness were possible.The significance of these results is discussed in terms of the development of screening techniques and breeding objectives.

scholarly journals Temperature-induced Glucosinolate Accumulation Is Associated with Expression of BrMYB Transcription Factors

HortScience ◽  
2013 ◽  
Vol 48 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Veronica L. Justen ◽  
Vincent A. Fritz
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Gene Expression Analysis ◽  
Tissue Type ◽  
Temperature Dependent ◽  
Temperature Regimes ◽  
Health Promoting ◽  
Transcription Factor Expression ◽  
Low Temperature Treatments

Turnips (Brassica rapa. subsp. rapa L.) produce glucosinolates (GSLs), thioglucosides whose hydrolyzed derivatives have been shown to provide chemopreventive benefits. Two cultivars of turnips [‘Just Right’ (JR) and ‘Scarlet Queen’ (SQ)] were grown under three different temperature regimes to assess the role of temperature on GSL production in roots and shoots. When compared with low-temperature treatments, high-temperature treatments increased total and individual GSLs in a tissue- and genotype-specific manner. When compared with low-temperature treatments, total GSLs were ≈70% and 130% higher in JR shoots and roots, respectively, grown at high-temperature treatments. High temperatures also increased total GSLs in SQ shoots and roots by ≈80% and 85%, respectively, when compared with low temperatures. Gluconasturtiin (GNS, 2-phenylethyl GSL) concentration was inversely correlated with temperature with high-temperature treatments resulting in 20% and 48% less GNS than low-temperature treatments in JR and SQ roots, respectively. The indolic GSL, 1-methoxyglucobrassicin (1MGB; 1-methoxy-3-ylmethyl GSL), was the root GSL most elevated by increased temperature resulting in a 1000% increase on average in both cultivars between the low- and high-temperature treatments. These results show promise for the use of temperature to enhance the health-promoting properties of turnip because 1MGB has potent chemopreventive effects. Gene expression analysis suggests that some BrMYB transcription factor expression levels are associated with temperature-dependent changes in GSL accumulation; however, this association varies between cultivar and tissue type.

OsSIG2A is required for chloroplast development in rice (Oryza sativa L.) at low temperature by regulating plastid genes expression

2019 ◽  
Vol 46 (8) ◽  
pp. 766 ◽  
Author(s):  
Yang Yu ◽  
Zhenling Zhou ◽  
Hanchun Pu ◽  
Baoxiang Wang ◽  
Yunhui Zhang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Low Temperatures ◽  
Chloroplast Development ◽  
Oryza Sativa L ◽  
Photosynthetic Apparatus ◽  
Development Stage ◽  
Specific Gene ◽  
Genes Expression ◽  
Young Leaves

The chloroplast is an essential photosynthetic apparatus that is more sensitive to low temperatures than other organelles. Sigma factors were revealed regulating specific gene expression for maintaining photosynthetic efficiency and adapting to physiological and environmental conditions. However, the regulatory mechanisms of SIG genes supporting chloroplast development under low temperature in rice have not yet been reported. Here, we uncovered the essential role of OsSIG2A in rice chloroplast development at low temperatures by a newly reported thermo-sensitive chlorophyll deficient 12 (tcd12) mutant, which exhibited albino leaves with decreased chlorophyll content and malformed chloroplasts at seedling stage under low temperature. OsSIG2A is a typical chloroplast-localised RNA polymerase sigma factor, and constitutively expresses in different rice tissues, especially for young leaves and stems. Moreover, the transcription level of both PEP- and NEP- dependent genes, which are necessary for chloroplast development at early leaf development stage, was greatly affected in the tcd12 mutant under low temperature. Taken together, our findings indicate that OsSIG2A is required for early chloroplast differentiation under low temperatures by regulating plastid genes expression.

DIAPAUSE TERMINATION AND MORPHOGENESIS OF HOLCOTHORAX TESTACEIPES RATZEBURG (HYMENOPTERA: ENCYRTIDAE), AN INTRODUCED PARASITOID OF THE SPOTTED TENTIFORM LEAFMINER, PHYLLONORYCTER BLANCARDELLA (F.) (LEPIDOPTERA: GRACILLARIIDAE)

1989 ◽  
Vol 121 (1) ◽  
pp. 65-74 ◽  
Author(s):  
T. Wang ◽  
J.E. Laing
Keyword(s):  
Low Temperature ◽  
Cold Storage ◽  
Host Species ◽  
Low Temperatures ◽  
Cold Period ◽  
Threshold Temperature ◽  
Thermal Constant ◽  
Emergence Percentage ◽  
Phyllonorycter Blancardella ◽  
Diapause Development

AbstractLow temperature is a major factor regulating diapause development in Holcothorax testaceipes Ratzeburg. Diapausing pupae required a cold period of 0°C, 5°C, or outdoor (≤0°C) for ca. 15 weeks to terminate diapause. The pupae required a further 21–27 days at 21°C for 50% emergence. Longer periods and higher temperatures of storage often were associated with shorter times of morphogenesis and duration of emergence. Percentage emergence of H. testaceipes was constant after various periods of cold storage at low temperatures. After storage at 0°C, pupae held at 21°C and a 16-h photophase reached 50% emergence sooner than those held at the same temperature but at a 12-h photophase. Photoperiod did not affect percentage or duration of emergence of the parasitoid. The threshold temperature for development of pupal H. testaceipes was estimated to be 9°C regardless of sex or host species. The thermal constant did not vary with sex of the parasitoids but differed significantly for H. testaceipes reared on Phyllonorycter ringoniella Matsumura (237 DD) and on Phyllonorycter blancardella (F.) (202 DD). Temperatures from 11 to 29°C did not affect percentage and duration of emergence from overwintered pupae, which were 75.5% and 2.4 days respectively, when reared on P. ringoniella, and 86.2% and 1.7 days respectively, on P. blancardella. These results suggest that H. testaceipes accepts P. blancardella as a host and will be synchronized with its development in Ontario.

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.

The Role of the Initiator System in the Synthesis of Acidic Multifunctional Nanoparticles Designed for Molecular Imprinting of Proteins

2020 ◽  
Vol 65 (1) ◽  
pp. 28-41
Author(s):  
Marwa Aly Ahmed ◽  
Júlia Erdőssy ◽  
Viola Horváth
Keyword(s):  
Acrylic Acid ◽  
Binding Affinity ◽  
Molecular Imprinting ◽  
Low Temperatures ◽  
Ammonium Persulfate ◽  
Sodium Bisulfite ◽  
Multifunctional Nanoparticles ◽  
High Affinity ◽  
Initiator System

Multifunctional nanoparticles have been shown earlier to bind certain proteins with high affinity and the binding affinity could be enhanced by molecular imprinting of the target protein. In this work different initiator systems were used and compared during the synthesis of poly (N-isopropylacrylamide-co-acrylic acid-co-N-tert-butylacrylamide) nanoparticles with respect to their future applicability in molecular imprinting of lysozyme. The decomposition of ammonium persulfate initiator was initiated either thermally at 60 °C or by using redox activators, namely tetramethylethylenediamine or sodium bisulfite at low temperatures. Morphology differences in the resulting nanoparticles have been revealed using scanning electron microscopy and dynamic light scattering. During polymerization the conversion of each monomer was followed in time. Striking differences were demonstrated in the incorporation rate of acrylic acid between the tetramethylethylenediamine catalyzed initiation and the other systems. This led to a completely different nanoparticle microstructure the consequence of which was the distinctly lower lysozyme binding affinity. On the contrary, the use of sodium bisulfite activation resulted in similar nanoparticle structural homogeneity and protein binding affinity as the thermal initiation.

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.

scholarly journals GERMINATION AND VIGOUR IN SEEDS OF THE COWPEA IN RESPONSE TO SALT AND HEAT STRESS

2019 ◽  
Vol 32 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Luma Rayane de Lima Nunes ◽  
Paloma Rayane Pinheiro ◽  
Charles Lobo Pinheiro ◽  
Kelly Andressa Peres Lima ◽  
Alek Sandro Dutra
Keyword(s):  
Salt Stress ◽  
Heat Stress ◽  
High Temperature ◽  
Low Temperature ◽  
Vigna Unguiculata ◽  
Salt Concentration ◽  
Dry Weight ◽  
Germination Percentage ◽  
Different Types ◽  
Different Temperatures

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.

scholarly journals Winter rye tolerance to low temperatures after seed treatment with surface barrier discharge

2021 ◽  
Vol 1787 (1) ◽  
pp. 012064
Author(s):  
S V Gundareva ◽  
A V Lazukin ◽  
N V Dorofeev ◽  
A G Romanov ◽  
S A Krivov
Keyword(s):  
Low Temperatures ◽  
Seed Treatment ◽  
Barrier Discharge ◽  
Surface Barrier ◽  
Winter Rye ◽  
Surface Barrier Discharge
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