scholarly journals Analytic studies in plant respiration. IV.—The relation of the respiration of potatoes to the concentration of sugars and to the accumulation of a depressant at low temperatures. Part I.—The effect of temperature-history on the respiration/sugar relation

1933 ◽  
Vol 112 (777) ◽  
pp. 316-335 ◽  
Keyword(s):  
Low Temperatures ◽  
Sugar Content ◽  
Sugar Concentration ◽  
Temperature History ◽  
Effect Of Temperature ◽  
Suitable Material ◽  
Exposure To Cold ◽  
Full Study ◽  
Plant Respiration ◽  
At Will

The relation of the rate of respiration to the concentration of sugars in the cell is a problem of great theoretical importance. There are some indications in the literature of the effect of high external concentrations of sugar in increasing the respiration, but no full study of the relation of respiration to the internal sugar concentration has yet been published. For the analysis of the effect of changing internal sugar concentration the potato is a most suitable material, since its excess of hydrolysable starch allows one to alter the sugar content by exposure to cold and so produce a range of sugar between 0.2 per cent. and 7.0 per cent. at will. Moreover it respiration (Muller-Thurgau, 1882 ; Hopkins, 1924 ; Bennett and Bartholomew, 1924).

scholarly journals Potential for the Postharvest Biological Control of Phthorimaea operculella (Lepidoptera, Gelechiidae) by Blattisocius tarsalis (Mesostigmata, Blattisociidae)

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 288
Author(s):  
Jorge Gavara ◽  
Ana Piedra-Buena ◽  
Estrella Hernandez-Suarez ◽  
Manuel Gamez ◽  
Tomas Cabello ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Storage Conditions ◽  
Control Agent ◽  
Phthorimaea Operculella ◽  
Effect Of Temperature ◽  
Potato Storage ◽  
Release Rates ◽  
Blattisocius Tarsalis ◽  
Predatory Capacity ◽  
Pest Density

Phthorimaea operculella is one of the most important pests causing damage to stored potatoes. In this work, the effect of temperature (at 10, 20 and 30 °C) on the predation of pest eggs by Blattisocius tarsalis was studied in the laboratory. In addition, the effect of three predatory release rates on two pest densities was studied under microcosm conditions. The results showed that B. tarsalis maintains its predatory capacity at low temperatures (10 °C), obtaining an efficiency of 49.66 ± 5.06% compared to the control. In turn, at 20 °C, a maximum efficacy of 78.17 ± 4.77% was achieved, very similar to that presented at 30 °C (75.57 ± 4.34%). Under microcosm conditions and at low pest density (10 eggs/container), the mortality due to the mite was 96.97 ± 3.03%, 81.82 ± 8.84%, and 84.85 ± 8.30%, respectively, for the three predatory release rates (5, 10 or 20 mites/container). At the high infestation level, the pest control ranged from 61.54 ± 9.21% to 92.31 ± 2.74%, depending on the predatory release rate. The results obtained show that B. tarsalis could be a relevant control agent against P. operculella under non-refrigerated potato storage conditions, as well as in the first stages of their storage under refrigerated conditions.

scholarly journals Flower mites decrease nectar availability in the rain-forest bromeliad Neoregelia johannis

2010 ◽  
Vol 26 (4) ◽  
pp. 373-379 ◽  
Author(s):  
Tadeu J. Guerra ◽  
Gustavo Q. Romero ◽  
Woodruff W. Benson
Keyword(s):  
Rain Forest ◽  
Sugar Content ◽  
Sugar Concentration ◽  
Production Rates ◽  
Nectar Production ◽  
Nectar Volume ◽  
Bombus Morio ◽  
Nectar Rewards ◽  
Flower Mites ◽  
Nectar Availability

Abstract:Nectarivorous flower mites can reduce the volume of nectar available to pollinators. The effects of the flower mite Proctolaelaps sp. on nectar availability in flowers of a melittophilous bromeliad Neoregelia johannis (Bromeliaceae) was evaluated in a coastal rain forest in south-eastern Brazil. In a randomized block experiment utilizing 18 flower pairs, one per bromeliad ramet, pollinators (Bombus morio) and mites were excluded, and then nectar volume, sugar concentration and sugar mass were quantified over the anthesis period. Mites significantly reduced nectar volume early in the morning (6h00–8h00), but not later (10h00–12h00). Mites decreased total volume of nectar available up to 22%. Sugar concentration in nectar was higher earlier in the morning, and decreased between 10h00–12h00. The pronounced consumption of nectar by mites during the period of higher sugar concentration reduced the total amount of sugar available to pollinators by 31%. This is the first study showing that flower mites decrease nectar rewards in a melittophilous plant. Because nectar volume by itself incompletely describes nectar production rates and the effects of nectar removal by flower mites on the availability of sugar, our study highlights the inclusion of sugar content in future studies assessing the effects of thieves on nectar production rates.

scholarly journals Characteristics of Black Ginseng (Panax ginseng C.A. Mayer) Production Using Ginseng Stored at Low Temperature after Harvest

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 98
Author(s):  
Hyo Bin Oh ◽  
Ji Won Lee ◽  
Da Eun Lee ◽  
Soo Chang Na ◽  
Da Eun Jeong ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Panax Ginseng ◽  
Low Temperatures ◽  
Sugar Content ◽  
Base Material ◽  
Free Sugar ◽  
Drying Process ◽  
Heat Treated ◽  
Black Ginseng

Ginseng processing often involves multiple drying and heat treatments. Ginseng is typically processed within one week of harvesting or is stored at low temperatures to prevent spoilage. Black ginseng (BG) is manufactured by repeating the heat treatment and drying process of ginseng several times. We compared the suitability of low-temperature stored ginseng (SG) and harvested ginseng (HG) as the components for black ginseng production. SG and HG were processed into black ginseng and the appearance change, free sugar content, and benzo[a]pyrene (BAP) content were observed. Appearance observations showed the SG to be suitable in terms of quality when heat-treated at a temperature of 95 ℃ or higher. The BAP content of the SG increased significantly as the steaming process was repeated. A maximum BAP concentration of 5.31 ± 1.12 μg/kg was measured in SG steamed from 2 to 5 times, making it unsuitable for processing into BG. SG and HG showed similar trends in the content of sucrose, fructose, and glucose during steaming. This study aimed to facilitate the proper choice of base material to improve the safety of black ginseng by limiting BAP production during processing.

Effect of temperature on transition and transversion mutagenesis: characterization of wild type and a mutator T4 DNA polymerase mutant

1984 ◽  
Vol 26 (3) ◽  
pp. 386-389 ◽  
Author(s):  
Linda J. Reha-Krantz ◽  
Sükran Parmaksizoglu
Keyword(s):  
Dna Polymerase ◽  
Low Temperatures ◽  
Bacteriophage T4 ◽  
Effect Of Temperature ◽  
In Vitro Mutagenesis ◽  
Wild Type ◽  
Mutational Site

The effect of temperature on genetically well-defined mutational pathways was examined in the bacteriophage T4. The mutational site was a T4 rII ochre mutant which could revert to rII+ via a transversion or to the amber convertant via a transition. Temperature did not strongly affect any of the pathways examined in a wild-type background; however, increased temperature reduced the mutational activity of a mutator DNA polymerase mutant. Possible models to explain the role of temperature in mutagenesis are discussed as well as the significance of low temperatures for in vitro mutagenesis reactions.Key words: bacteriophage T4, mutator, transition, transversion, temperature effects.

The function of the sarcoplasmic reticulum is not inhibited by low temperatures in trout atrial myocytes

2001 ◽  
Vol 281 (6) ◽  
pp. R1902-R1906 ◽  
Author(s):  
Leif Hove-Madsen ◽  
Anna Llach ◽  
Lluis Tort
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Low Temperatures ◽  
Experimental Temperature ◽  
Effect Of Temperature ◽  
Fast Time ◽  
Atrial Myocytes ◽  
Patch Clamp Technique ◽  
Two Temperatures ◽  
Perforated Patch Clamp ◽  
The Relationship

The effect of temperature on sarcoplasmic reticulum (SR) Ca2+ uptake and release was measured in trout atrial myocytes using the perforated patch-clamp technique. Depolarization of the myocyte for 10 s to different membrane potentials ( V m) induced SR Ca2+ uptake. The relationship between V m and SR Ca2+ uptake was not significantly changed by lowering the experimental temperature from 21 to 7°C, and the relationship between total cytosolic Ca2+and SR Ca2+ uptake was similar at the two temperatures with a pooled Vmax = 66 amol/pF and K 0.5 = 4 amol/pF. Quantification of the Ca2+ release from the SR elicited by 10-ms depolarizations to different V m showed an increasing SR Ca2+ release at more positive V mbetween −50 and +10 mV, whereas SR Ca2+ release stagnated between +10 and +50 mV. Lowering of the temperature did not affect this relationship significantly, giving an SR Ca2+ release of 1.71 and 1.54 amol/pF at 21 and 7°C, respectively. Furthermore, clearance of the SR Ca2+ content slowed down inactivation of the L-type Ca2+ current at both temperatures (the fast time constant increased significantly from 10.4 ± 1.9 to 15.0 ± 2.0 ms at 21°C and from 38 ± 15 to 73 ± 24 ms at 7°C). Thus the SR has the capacity to remove the entire Ca2+ transient at physiologically relevant stimulation frequencies at both 21 and 7°C, although it is estimated that ∼40% of the total Ca2+ transient is liberated from and reuptaken by the SR with continuous stimulation at 0.5 Hz independently of the experimental temperature.

scholarly journals The growth of silver iodide films

1929 ◽  
Vol 125 (797) ◽  
pp. 370-394 ◽  
Keyword(s):  
Parabolic Equation ◽  
Gas Phase ◽  
Low Temperatures ◽  
Silver Iodide ◽  
Film Growth ◽  
Oxide Films ◽  
Gravimetric Method ◽  
Instructive Case ◽  
At Will ◽  
Iodide Film

It is now well established that a large class of important chemical reactions is controlled by the growth of obstructive films, but our knowledge of the mechanism of the growth of such films—especially at low temperatures—is still very imperfect. The present paper describes a detailed study of a particularly instructive case of film-growth, the action of iodine on silver; this reaction was chosen because silver iodide films—in contrast with oxide films—reach visible thickness rapidly at ordinary temperatures. The optical properties of these films have already been studied by Wernick, whilst much information regarding the velocity of film-growth has been obtained by Tammanm by Kohlschutter and Krahenbiihl, and by Hartung. Tammann used the interference colour as the means of arriving at the thickness of the film; this method has certain unique advantages, but the more recent work of Tammann and Bockow has indicated that—in the case of oxide-films at least—the particular form of the method employed gives values for the thickness differing widely from those obtained by the gravimetric method. Tammann expressed the relation between the thickness ( y ) and the time ( t ) by the parabolic equation y 2 = 2 pt , where p is a. constant. Kohlschütter and Krähenbiihl, and also Hartung, used microgravimetric methods to determine the amount of iodine taken up, and obtained curves connecting thickness and time ; these curves do not appear to follow the parabolic equation. All the experimenters mentioned used iodine vapour to attack the silver, but the concentration of iodine in the gas phase was not directly determined. In all cases the surfaces were prepared in air, and the possible effect of exposure to oxygen was not considered; yet in several of the reactions of copper and iron, pre-exposure to air or oxygen is known greatly to modify the result, owing to the fact that an oxide-film may become protective before reaching the thickness needed for interference colours. It may be mentioned that after exposure to vapour, the colour produced on metallic specimens is usually not uniform, but indicates a greater film-thickness near the edge. In the present research, it was decided to use a solution of iodine in an organic solvent; in this case, the concentration could be fixed or varied at will, and in general uniform colouration (indicating uniform thickness) could be obtained. Moreover, abrasion could be conducted, if required, below the surface of the solvent, instead of in air. Chloroform was .found to be a suitable liquid, since, whilst freely dissolving iodine, it had no appreciable solvent action on a silver iodide film.

Atomistic simulation for configuration evolution and energetic calculation of crack in body-centered-cubic iron

2006 ◽  
Vol 21 (10) ◽  
pp. 2542-2549 ◽  
Author(s):  
Li-Xia Cao ◽  
Chong-Yu Wang
Keyword(s):  
Low Temperatures ◽  
Crack Tip ◽  
Dislocation Nucleation ◽  
Effect Of Temperature ◽  
Body Centered Cubic ◽  
Partial Dislocations ◽  
Higher Temperature ◽  
Crack Blunting ◽  
Increasing Temperature ◽  
Extended Dislocation

The molecular dynamics method has been used to simulate mode I cracking in body-centered-cubic iron. Close attention has been paid to the process of the atomic configuration evolution of the cracks. The simulation shows that at low temperatures, partial dislocations are emitted before the initiation of crack propagation, subsequently forming the stacking faults or multilayer twins on {112} planes, and then brittle cleavage and extended dislocation nucleation are observed at the crack tip accompanied by twin extension. These results are in agreement with the experimental observation that twinning and fracture processes cooperate at low temperatures. Furthermore, an energetics analysis has been made on the deformation behavior observed at the crack tip. The effect of temperature on the fracture process is discussed. At the higher temperature, plastic deformation becomes easier, and crack blunting occurs. With increasing temperature, the fracture resistance increases, and the effect of the lattice trapping can be weakened by thermal activation.

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