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.

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.

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.

scholarly journals Experimental Investigation of Rate-Dependent Inner Hysteresis Loops in PZT

2005 ◽  
Vol 881 ◽  
Author(s):  
Alexander York ◽  
Stefan Seelecke
Keyword(s):  
Experimental Investigation ◽  
Systematic Study ◽  
Domain Switching ◽  
Piezoelectric Materials ◽  
Relaxation Times ◽  
Hysteresis Loops ◽  
Loading Rates ◽  
Rate Dependent ◽  
Realistic Modeling ◽  
Kinetics Of

AbstractThe rate-dependence of piezoelectric materials resulting from the kinetics of domain switching is an important factor that needs to be included in realistic modeling attempts. This paper provides a systematic study of the rate-dependent hysteresis behavior of a commercially available PZT stack actuator. Experiments covering full as well as minor loops are conducted at different loading rates with polarization and strain recorded. In addition, the creep behavior at different constant levels of the electric field is observed. This provides evidence of kinetics being characterized by strongly varying relaxation times that can be associated with different switching mechanisms.

KINETICS OF MERISTEM CELLS IN SUB-POPULATIONS OF THE ROOT APEX OF AVENA SATIVA L.

1981 ◽  
Vol 30 (1-2) ◽  
pp. 9-17 ◽  
Author(s):  
P. A. A. Harkes ◽  
Claartje A. M. Tetteroo-Tempelman
Keyword(s):  
Avena Sativa ◽  
Root Apex ◽  
Kinetics Of

Interfacial Segregation Effects in Mixtures of Homopolymers with Copolymers.

1989 ◽  
Vol 171 ◽  
Author(s):  
Vijay S. Wakharkar ◽  
Thomas P. Russell ◽  
Vaughn R. Deline
Keyword(s):  
Mass Spectroscopy ◽  
Diblock Copolymers ◽  
Large Range ◽  
Surface Enrichment ◽  
Molecular Weights ◽  
Polymer Interface ◽  
Segregation Process ◽  
Interfacial Segregation ◽  
Kinetics Of ◽  
Secondary Ion

ABSTRACTSecondary Ion Mass Spectroscopy (SIMS) has been used to study the surface and interfacial segregation of diblock copolymers in mixtures of the copolymer in the homopolymer. Symmetric, diblock copolymers of polystyrene (PS) and poly(methyl methacrylate) (PMMA), in either the PS or the PMMA homopolymers were investigated. In mixtures of the copolymer with the PS homopolymer, systematic surface enrichment of the copolymer as well as segregation of the copolymer to the polymer/Si interface or in the case of bilayered filmsto the polymer/polymer interface occurs with annealing treatments. These segregation effects persist over a large range of homopolymer molecular weights with changes in the kinetics of the segregation process being predominant.

scholarly journals Spectroscopic forms of carbonmonoxi-cytochrome oxidase

1979 ◽  
Vol 183 (2) ◽  
pp. 375-379 ◽  
Author(s):  
K de Fonseka ◽  
B Chance
Keyword(s):  
Low Temperature ◽  
Cytochrome Oxidase ◽  
Systematic Study ◽  
Residual Effect ◽  
Difference Spectra ◽  
Temperature Recording ◽  
Devitrification Process ◽  
Kinetics Of

A systematic study of the errors of low-temperature recording of kinetics of the cytochrome oxidase-CO reaction had identified the classic devitrification process of Keilin & Hartree [(1950) Nature (London)165, 504-505]. The methodology described here minimizes this effect, and the computation methods afford appropriate ways of detecting a residual effect. Thus it has been possible to identify that absorption difference spectra and kinetics of the reaction of fully reduced or half-reduced cytochrome oxidase with CO indicate only one spectroscopic form of the respective carbonmonoxi-cytochrome oxidase.

scholarly journals Identification of CD13, CD107a, and CD164 as novel basophil-activation markers and dissection of two response patterns in time kinetics of IgE-dependent upregulation

Cell Research ◽  
2005 ◽  
Vol 15 (5) ◽  
pp. 325-335 ◽  
Author(s):  
Florian HENNERSDORF ◽  
Stefan FLORIAN ◽  
Andreas JAKOB ◽  
Katharina BAUMGÄRTNER ◽  
Karoline SONNECK ◽  
...  
Keyword(s):  
Basophil Activation ◽  
Response Patterns ◽  
Activation Markers ◽  
Kinetics Of
Sign in / Sign up

Export Citation Format

Share Document