scholarly journals Effect of photostimulation on biopotentials of maize leaves in conditions of thermal irritation

2018 ◽  
Vol 9 (3) ◽  
pp. 347-352
Author(s):  
M. P. Motsnyj ◽  
О. V. Elina ◽  
N. P. Botsva ◽  
S. O. Kochubey
Keyword(s):  
Continuous Light ◽  
Light Stimulation ◽  
Cold Stimulation ◽  
Simultaneous Exposure ◽  
Background Light ◽  
Total Potential ◽  
Maize Leaves ◽  
Continuous Background ◽  
Total Action ◽  
External Conditions

Plant biopotentials can be used to evaluate their functional state and mechanisms for adaptation to changes in external conditions of their cultivation. The paper is devoted to the experimental study of the dynamics of total potential of maize leaves caused by cold and heat stimuli on the background of photopotential during continuous light stimulation. In the experiments, a specially designed stimulator was used that allowed simultaneous exposure of the plant to light and to thermal irritation. Studies have shown that background continuous light stimulation with white light with a brightness of 250 lux results in an increase in the amplitude of total action potentials caused by rhythmic cold stimulation. The amplitudes of "cold" potentials grew synchronously with the growth of the potential of hyperpolarization under the influence of photostimulation. With the termination of light stimulation, the amplitude of "cold" potentials stabilized. It is assumed that this effect is due to an increase in the amplitude of potentials of action, which correspond to the total potential due to the hyperpolarization of the membranes of the cells that generate them. Such hyperpolarization is due to an increase in the active transport of H+ ions through the membrane of cells in the light phase of photosynthesis. It has been shown that during pulsed heat stimulation, the preliminary continuous background light stimulation results in a decrease in the amplitude of "heat" potentials, a reduction in their duration, and the appearance of a short latent hyperpolarization potential in their initial phase. It is established that these changes correlate with the growth of the potential of hyperpolarization caused by background light stimulation. Based on the analysis of the detected changes, it was deduced that an increase in the level of hyperpolarization increases the threshold of excitability of cell membranes generating these potentials. When the photostimulation was switched off, the level of hyperpolarization decreased, but the amplitudes of the "heat" potentials increased. At the same time, the duration of the potentials increased sharply, and the elements characteristic of the variable potentials appeared in them. This may indicate a significant increase in sensitivity to heat irritation with a decrease in the level of hyperpolarization.

scholarly journals Photoregulation of the Cat2 and Cat3 catalase genes in pigmented and pigment-deficient maize: the circadian regulation of Cat3 is superimposed on its quasi-constitutive expression in maize leaves.

Genetics ◽  
1991 ◽  
Vol 127 (3) ◽  
pp. 601-607 ◽  
Author(s):  
A Acevedo ◽  
J D Williamson ◽  
J G Scandalios
Keyword(s):  
Allelic Variation ◽  
Constitutive Expression ◽  
Continuous Light ◽  
State Level ◽  
Sampling Period ◽  
Wild Type ◽  
Dark Cycle ◽  
Light Regimes ◽  
Maize Leaves ◽  
Rna Accumulation

Abstract We have investigated the accumulation of Cat2 and Cat3 catalase transcripts in 6-7-day postimbibition leaves of normally pigmented and pigment-deficient maize seedlings under different light regimes. In seedlings of normal inbred maize lines Cat2 mRNA accumulates to significantly higher levels in either continuous light or a diurnal light/dark cycle than in continuous dark. In contrast to the high levels of the Cat2 message observed in their wild-type siblings, carotenoid-deficient mutants accumulate Cat2 mRNA at barely detectable levels. Mutants deficient in chlorophylls, but having normal carotenoid levels, accumulate normal levels of Cat2 mRNA. This suggests that both light and carotenoids are required for the normal accumulation of the Cat2 message. The steady-state level of Cat3 RNA exhibits a dramatic diurnal variation when seedlings are grown under a 24-hr light/dark cycle. We have previously shown that this variation is at the level of Cat3 gene transcription and is under the control of a novel circadian rhythm. In this study we show that both pigment-deficient mutants and their wild-type siblings exhibit the normal diurnal pattern of Cat3 RNA accumulation. This indicates that photosynthetic pigments, allelic variation, and genetic background do not directly affect the temporal pattern of Cat3 accumulation in leaves. We observed, however, that when normal plants are grown in either continuous light or continuous dark, the Cat3 transcript in leaves is present at uniformly high levels throughout the 24-hr sampling period.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Influence of Background Illumination on the Photoresponse of Micropixel Avalanche

2019 ◽  
Vol 4 (4) ◽  
pp. 108-110
Author(s):  
Elmira A. Jafarova ◽  
Ali Huseyn A. Dovlatov ◽  
Lala A. Aliyeva ◽  
Eldar S. Tapdygov ◽  
Kamala A. Askerova
Keyword(s):  
Output Signal ◽  
Single Photon ◽  
Avalanche Photodiodes ◽  
Continuous Light ◽  
Front Surface ◽  
Light Sources ◽  
Structural Components ◽  
Entire Surface ◽  
Background Light ◽  
Wide Range

Micropixel avalanche photodiodes (MAPD) with deeply buried pixels have no structural components made on its front surface and therefore almost its entire surface is photosensitive. MAPD possesses high photodetection efficiency (PDE), multiplication gain ~105, photosensitivity from a single photon and wide range of dynamic linearity of photoresponse up to 5×103 photons/mm2. The influence of the background light on the gain and linearity of the photoresponse of the MAPD-3N type samples was investigated. External light sources have different effects on the output signal of MAPD whichever it is pulsed or continuous light. It is shown that in contrast to pulsed external light, the light from the permanent source leads to reducing of the output signal. But a constant background light does not deteriorate the linearity of the photoresponse in the whole range of linearity of the device.

scholarly journals Вплив термічної стимуляції на біопотенціали листя кукурудзи

2010 ◽  
Vol 1 (2) ◽  
pp. 65-70
Author(s):  
M. P. Motsnyj ◽  
N. P. Botsva ◽  
S. V. Vlasova ◽  
О. V. Elina ◽  
I. P. Matvij
Keyword(s):  
Heating Rate ◽  
Qualitative Difference ◽  
Time Interval ◽  
Amplitude Dependence ◽  
Cold Stimulation ◽  
Potential Amplitude ◽  
Heat Stimulation ◽  
Heating And Cooling ◽  
Maize Leaves ◽  
The Difference

Dynamics of maize leaves' biopotentials evoked by cold- and heat stimuli with two frequencies 0.05 and 0.1 Hz is analyzed. Potential amplitude dependence of heating rate and time interval between first and following stimuli during both heating and cooling was discovered. It is ascertained that following potentials' amplitude increases in time during heat stimulation and decreases in time during cold stimulation. Qualitative difference in the reaching of potential stabilization is established for both stimulation frequencies; and probable reasons of the difference are analyzed. Potential stabilization levels are fixed for each series of experiment.

scholarly journals Effect of duration of exposure to continuous illumination on reversibility of microcirculatory disorders in experimental desynchronosis

2018 ◽  
Vol 17 (3) ◽  
pp. 129-134
Author(s):  
N. Ye. Tereshkina ◽  
O. V. Zlobina ◽  
A. N. Ivanov ◽  
A. A. Dolgov
Keyword(s):  
Adaptive Response ◽  
Continuous Light ◽  
Light Regime ◽  
Male Rats ◽  
Continuous Illumination ◽  
Light Stimulation ◽  
Doppler Flowmetry ◽  
Microcirculatory Disorders ◽  
Group 2 ◽  
Group 1

The aim of the study was to assess the degree of reversibility of microcirculatory disorders in the modeling of LL desynchronosis depending on the duration of exposure to continuous illumination. Material and methods. Microcirculation was studied by laser Doppler flowmetry. Male rats were subjected to continuous light stimulation for 10 (group 1) and 21 (group 2) days, and then kept under natural light for 21 days. Results. Continuous lighting caused a disturbance of microhemodynamics which tended to recover after normalization of the light regime in the rats of group 1. In the animals of group 2, circulation in microvessels was not restored. Conclusions. Reversibility of the changes can serve as a criterion for distinguishing the adaptive response to inadequate photoperiod and LL-desynchronosis.

Interaction of divalent metal ions with the NADP+-malic enzyme from maize leaves

1991 ◽  
Vol 81 (4) ◽  
pp. 462-466 ◽  
Author(s):  
Maria Fabiana Drincovich ◽  
Alberto A. Iglesias ◽  
Carlos S. Andreo
Keyword(s):  
Metal Ions ◽  
Malic Enzyme ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Maize Leaves

The influence of external conditions on sound pressure in the pistonphone at the infrasound frequency range

2020 ◽  
pp. 67-72
Author(s):  
A. V. Konkov ◽  
D. V. Golovin
Keyword(s):  
Environmental Conditions ◽  
Sound Pressure ◽  
Primary Method ◽  
Frequency Range ◽  
External Conditions ◽  
Numerical Estimations

The influence of environmental conditions on a sound pressure reproduced by the primary method in the measuring chambers of the Pistonphone in the frequency range from 1 mHz to 250 Hz is estimated. Numerical estimations of influence of environmental conditions on sound pressure in pistonphone measuring chambers are given and special requirements to system of maintenance of required external conditions are specified.

The Investment Climate in Russia

2006 ◽  
pp. 48-77
Author(s):  
Article Editorial
Keyword(s):  
Money Demand ◽  
State Level ◽  
Decision Making Process ◽  
Investment Climate ◽  
Operational Environment ◽  
Gdp Growth Rate ◽  
External Conditions ◽  
Potential Gdp ◽  
The Government ◽  
Economic Boom

During the last six years, exceptionally favourable external conditions for an upsurge of the domestic economy have been developed. However, they failed to result in an economic boom, which has been estimated by the authors as quite possible. One of the reasons for this - deterioration of the investment climate in the country that caused a decline of business activities and money demand decrease thus leading to reduction of potential GDP growth rate. The accumulated modernisation problems cannot be resolved without increasing the economic dynamics. But this requires an economic policy able to facilitate predictability of Russian business operational environment, to protect it legally, to secure a system of partnership relations with the government and to respect the interests of the main participants in the state level decision-making process concerning business undertakings and investment climate.

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