Geotropic response patterns of the Avena coleoptile. II. Induction at low temperature

1973 ◽  
Vol 51 (5) ◽  
pp. 1023-1027 ◽  
Author(s):  
Barbara Gillespie Pickard
Keyword(s):  
Low Temperature ◽  
Avena Sativa ◽  
Response Patterns ◽  
Avena Coleoptile ◽  
Primary Reactions ◽  
Reception System

The gravity reception system of the coleoptile of Avena sativa L., cv. Victory, deteriorates progressively and rapidly at 2 °C. In contrast, at 2 °C there is no progressive diminution of the ability of the geotropically induced coleoptile, when returned from 2 °C to 25 °C, to carry out the secondary processes leading to curvature.For the Avena coleoptile, it is impossible to isolate primary reactions by means of low temperature as has been reported successful for the Helianthus hypocotyl; induction and curving proceed concurrently at 2 °C.

Geotropic response patterns of the Avena coleoptile. I. Dependence on angle and duration of stimulation

1973 ◽  
Vol 51 (5) ◽  
pp. 1003-1021 ◽  
Author(s):  
Barbara Gillespie Pickard
Keyword(s):  
Linear Function ◽  
Systematic Study ◽  
Avena Sativa ◽  
Large Range ◽  
Vertical Position ◽  
Response Patterns ◽  
Pressure Data ◽  
Avena Coleoptile ◽  
Perpendicular Component ◽  
Kinetics Of

A systematic study was made of the kinetics of geotropic response of coleoptiles of Avena sativa L., cv. Victory.Over a reasonably large range, response could be approximated as a linear function of stimulus duration for coleoptiles stimulated by horizontal placement. The threshold for induction of subsequently visible curvature was about 20 s, but evidence is presented that inductive reactions begin as soon as the coleoptile is set on its side. Corroboratively, intermittently administered stimuli as brief as 0.5 s were summed without loss.Plants were stimulated at selected angles between 0° and 90° from the vertical position of equilibrium for an arbitrarily selected time, and response was linearly dependent on the perpendicular component of acceleration. This dependence supports the hypothesis that geotropism is a response to the differential exertion of pressure. Data for supplementary angles are also consistent with the pressure hypothesis.

Inhibition by carbon dioxide of the phototropic response of the Avena coleoptile to blue light

1987 ◽  
Vol 65 (3) ◽  
pp. 488-490 ◽  
Author(s):  
Gordon I. McIntyre
Keyword(s):  
Carbon Dioxide ◽  
Blue Light ◽  
Avena Sativa ◽  
Water Saturation ◽  
Phototropic Response ◽  
Avena Coleoptile ◽  
Inhibition Of Growth ◽  
Saturated Water ◽  
Coleoptile Elongation

When intact oat coleoptiles (Avena sativa var. Harmon) were submerged in water, saturation of the water with CO2 promoted their elongation but eliminated their phototropic response to blue light. Increasing the pH of the CO2-saturated water prevented the promotion of coleoptile elongation but did not prevent the elimination of the phototropic response. In air, phototropic curvature was significantly reduced by 10% CO2 and was eliminated by 30%, without any reduction in growth. It is postulated that the increase in CO2 concentration may eliminate the phototropic curvature of the coleoptile by preventing the light-induced inhibition of growth on the illuminated side of the organ. Possible mechanisms are briefly discussed.

Low-temperature luminescence characterization of 124-kilodalton phytochrome from Avena sativa

Biochemistry ◽  
1983 ◽  
Vol 22 (12) ◽  
pp. 2846-2851 ◽  
Author(s):  
Tai An Cha ◽  
August H. Maki ◽  
J. Clark Lagarias
Keyword(s):  
Low Temperature ◽  
Avena Sativa

scholarly journals Improvement of the Modeling of the Low-Temperature Oxidation of n-Butane: Study of the Primary Reactions

2012 ◽  
Vol 116 (24) ◽  
pp. 6142-6158 ◽  
Author(s):  
Maximilien Cord ◽  
Baptiste Sirjean ◽  
René Fournet ◽  
Alison Tomlin ◽  
Manuel Ruiz-Lopez ◽  
...  
Keyword(s):  
Low Temperature ◽  
Low Temperature Oxidation ◽  
Temperature Oxidation ◽  
Primary Reactions

Low-temperature and time-resolved spectroscopic characterization of the LOV2 domain of Avena sativa phototropin 1

2004 ◽  
Author(s):  
Magdalena Gauden ◽  
Sean Crosson ◽  
I. H. M. van Stokkum ◽  
Rienk van Grondelle ◽  
Keith Moffat ◽  
...  
Keyword(s):  
Low Temperature ◽  
Avena Sativa ◽  
Spectroscopic Characterization ◽  
Time Resolved

Changes in the hemicellulosic polysaccharides of Avena coleoptile cell walls during growth of intact seedlings

1988 ◽  
Vol 66 (5) ◽  
pp. 949-954 ◽  
Author(s):  
M. Teresa Herrera ◽  
Ignacio Zarra
Keyword(s):  
Molecular Weight ◽  
Avena Sativa ◽  
Cell Walls ◽  
Average Molecular Weight ◽  
Relative Content ◽  
The Other ◽  
Polysaccharide Fraction ◽  
Avena Coleoptile ◽  
Main Component ◽  
Soluble Part

The variations taking place in the major polysaccharides of the cell wall of Avena sativa L. cv. Victory coleoptiles were studied during growth. Two fractions were obtained, one corresponding to cellulose and the other to the hemicelluloses. The relative content of cellulose was greater in the basal regions of the coleoptiles and the proportion of this polysaccharide fraction increased in all regions during growth. The hemicellulosic fraction was composed of two parts, an insoluble one designated the HC A hemicellulosic fraction, whose main component was seen to be an insoluble xyloglucan, and a soluble part designated the HC B hemicellulosic fraction, composed of an arabinoxylan and a (β1-3)- or (β1-4)-glucan. This latter was degraded during the growth of the coleoptiles. The average molecular weight of hemicelluloses HC A and HC B decreased from the sub-apical zones to the basal zones of the coleoptiles; this was related to the growth capacity of each of the regions into which the coleoptiles were divided.

GERMINATION RESPONSE OF DORMOAT SEEDS TO LOW TEMPERATURE AND GIBBERELLIN

1972 ◽  
Vol 52 (3) ◽  
pp. 295-303 ◽  
Author(s):  
C. J. ANDREWS ◽  
V. D. BURROWS
Keyword(s):  
Abscisic Acid ◽  
Low Temperature ◽  
Gibberellic Acid ◽  
Seed Dormancy ◽  
Avena Sativa ◽  
Low Temperatures ◽  
Dry Storage ◽  
Secondary Dormancy ◽  
Derivatives Of ◽  
Different Levels

Dormoats are derivatives of crosses between Avena sativa L. and A. fatua L., designed to be sown in the fall to germinate the following spring. Strains vary in levels of seed dormancy at harvest and in their rates of after-ripening in dry storage. Germination of the seeds is stimulated by gibberellic acid. Embryos isolated from dormant seeds exhibit no dormancy but their germination is prevented by abscisic acid. Low temperatures (ca. 7 C) stimulate germination to different levels in various strains. Seeds enter a secondary dormancy when they fail to germinate in the imbibed state due to primary domancy. Seeds with secondary dormancy are not stimulated to germinate by low temperatures until partial after-ripening of the seeds in the dry state has occurred, but germination is stimulated by gibberellic acid without after-ripening. Secondary dormancy is proposed as a factor in the maintenance of undergerminated seed in the soil from fall planting into winter.

scholarly journals Increasing Low-Temperature Toughness of 09Mn2Si Steel through Lamellar Structuring by Helical Rolling

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 352
Author(s):  
Sergey Panin ◽  
Ilya Vlasov ◽  
Dmitry Moiseenko ◽  
Pavel Maksimov ◽  
Pavlo Maruschak ◽  
...  
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Hsla Steel ◽  
High Strength ◽  
Fracture Mechanisms ◽  
Response Patterns ◽  
Helical Rolling ◽  
Fracture Surfaces ◽  
Initiation And Propagation ◽  
Low Temperature Impact Toughness

The aim of the paper was to investigate the helical rolling parameters (a number of passes) for the microstructural modification and the low-temperature impact toughness improvement of the 09Mn2Si High Strength Low-Alloyed (HSLA) steel. In order to achieve this purpose, work spent to crack initiation and propagation was analyzed and compared with patterns of fracture surfaces. The microstructure and impact toughness values were presented in the temperature range from +20 to –70°C. Also, the fracture mechanisms in individual regions on the fracture surfaces were discussed. In addition, a methodology for computer simulation of the process was developed and implemented within the framework of the excitable cellular automata method and its integration with the kinetic theory of fracture. Finally, a theoretical analysis of the effect of grain shapes and orientations on the strain response patterns of a certain meso-volume simulating the material after the helical rolling was carried out.

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