The role of endogenous ethylene in the expansion of Helianthus annuus leaves

The possible role of ethylene in leaf expansion of the primary leaves of sunflower plants (Helianthus annuus) was studied. Our lowest application of ethephon promoted expansion of primary leaves. Higher concentrations of ethephon, and a range of concentrations of 1-aminocyclopropane-1-carboxylic acid, increased endogenous ethylene concentration and caused a reduction in the area of the primary leaves. The inhibition in leaf expansion induced by ethephon and 1-aminocyclopropane-1-carboxylic acid was reversed by pretreating the plants with an inhibitor of ethylene action, namely silver thiosulphate. Treating leaves with lower concentrations of aminoefhoxyvinylglycine reduced ethylene production and stimulated leaf expansion. This effect of aminoethoxyvinylglycine could be nullified by pretreating the plants with 1-aminocyclopropane-1-carboxylic acid. Treatment with silver thiosulphate enhanced leaf expansion. This indicates that endogenous ethylene normally plays a significant role in leaf expansion. Flooded and gravistimulated plants produced more ethylene and had smaller leaves. This could suggest that the increased ethylene is the main cause of the slowed leaf growth, however, only in some cases were we able to partially reverse the effect of flooding with silver thiosulphate. This indicates that there are probably many factors, in addition to increased ethylene, that inhibit leaf expansion in flooded and gravistimulated plants. Key words: ethylene, leaf expansion.

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Light regulation of endogenous salicylic acid levels in hypocotyls of Helianthus annuus seedlings

Botany ◽

10.1139/b10-042 ◽

2010 ◽

Vol 88 (7) ◽

pp. 668-674 ◽

Cited By ~ 18

Author(s):

Leonid V. Kurepin ◽

Linda J. Walton ◽

David M. Reid ◽

C. C. Chinnappa

Keyword(s):

Salicylic Acid ◽

Helianthus Annuus ◽

Leaf Growth ◽

Stem Elongation ◽

Light Regulation ◽

Shade Avoidance ◽

Light Conditions ◽

Direct Role ◽

Positive Effects

Plants growing in canopy shade typically exhibit increased stem elongation and reduced leaf growth. This is as a result of direct interactions between plant photoreceptors sensing the change (reduction) in the ratio of red to far-red (R/FR) light and photosynthetically active radiation (PAR) and plant hormones, and regulating these morphological traits. The effect of the varying light conditions found in shade on endogenous salicylic acid (SA) content was tested, and the possible role of SA in shade avoidance by sunflower ( Helianthus annuus L.) hypocotyls was examined. A logarithmic increase in PAR irradiance levels increased endogenous SA levels roughly 10-fold. Separation of individual light wavelengths (R, FR, and blue) constituting the PAR irradiance of sunlight, established that only FR light had significant and positive effects on endogenous SA levels. Further, a low R/FR ratio significantly increased the endogenous SA content in hypocotyls compared with normal and high R/FR ratios. Uncoupling the effect of R/FR ratio and PAR irradiance on endogenous SA content demonstrated that PAR irradiance is a much stronger signal than FR light-enrichment. Thus, while a low R/FR ratio increases the SA content in sunflower hypocotyls, low PAR, the other component of canopy shade, decreases the SA content much more effectively than low R/FR ratio increases it. Therefore, it appears that SA probably has no direct role in shade avoidance effects.

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The Effects of Perfluoroalkyl Carboxylic Acid Coating of Al Particles to Flame Propagation

Volume 3: Combustion Science and Engineering ◽

10.1115/imece2009-10078 ◽

2009 ◽

Author(s):

B. Dikici ◽

M. L. Pantoya ◽

R. J. Jouet

Keyword(s):

Reaction Mechanism ◽

Carboxylic Acid ◽

Metal Oxide ◽

Flame Propagation ◽

Thermal Equilibrium ◽

Acid Treatment ◽

Heat Of Combustion ◽

Oxide Composites ◽

Acid Coating

In this study, two types of nano-Al/metal oxide composites are examined. The first Al sample is passivated with Al2O3 and treated with perfluoroalkyl carboxylic acid (C13F27COOH). The second Al sample is devoid of an alumina shell and instead passivated with perfluoroalkyl carboxylic acid (C13F27COOH). The goal of this study is to understand the role of the passivation shell and associated reaction mechanism on flame propagation. Results show that when there is no alumina passivation shell encasing the Al core the flame propagation rates are reduced by two orders of magnitude. All flame propagation experiments were performed in a confined flame tube apparatus which may not be ideal for characterizing materials with significantly different ignition sensitivities. Results indicate that flame speeds measured with this apparatus are dependent on the ignition sensitivity of the mixture. Acid treated Al particles are shown to be roughly five times less ignition sensitive than the Al particles with no acid treatment; however, both particles produce roughly the same heat of combustion in thermal equilibrium measurements.

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Stem and leaf growth of alpine sun and prairie shade ecotypes of Stellaria longipes under different photoperiods: role of ethylene

Canadian Journal of Botany ◽

10.1139/b06-111 ◽

2006 ◽

Vol 84 (9) ◽

pp. 1496-1502 ◽

Cited By ~ 5

Author(s):

Linda J. Walton ◽

Leonid V. Kurepin ◽

David M. Reid ◽

C.C. Chinnappa

Keyword(s):

Leaf Growth ◽

Stem Elongation ◽

Leaf Length ◽

Leaf Expansion ◽

Alpine Plants ◽

Growth Responses ◽

Stellaria Longipes ◽

Length And Area ◽

Radiation Conditions

Plant ecotypes of Stellaria longipes Goldie from competitive, shade-adapted prairie habitat and less competitive, nonshaded alpine habitat were subjected to shortened or extended photoperiod conditions. Increasing daylength was positively correlated to increased stem elongation in both ecotypes. Leaf length and area for shade (prairie) plants was significantly altered with increased photoperiods, whereas sun (alpine) plants exhibited minimal leaf expansion in response to increased photoperiod. Increased ethylene evolution in the alpine genotype during rapid stem elongation and extended photoperiods suggests that ethylene plays a growth regulatory role in this sun-adapted genotype. The prairie genotype evolved less ethylene during these same periods, indicating either a diminished requirement for elevated ethylene to effect elongation and leaf expansion responses or possibly increased ethylene sensitivity because of interactions with other hormones, such as gibberellin or auxin. The sun genotype consistently produced more ethylene than the shade genotype under all photoperiod treatments. We conclude that photoperiod alters stem elongation and leaf expansion responses; similar trends were observed for extended photoperiods as were observed for shaded conditions, specifically low light intensity (photosynthetically active radiation) conditions. Further, ethylene levels altered during these responses, especially in sun-adapted alpine plants, which suggests that ethylene is involved in these growth responses.

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Involvement of ethylene in ectomycorrhiza formation and dichotomous branching of roots of mugo pine seedlings

Canadian Journal of Botany ◽

10.1139/b89-067 ◽

1989 ◽

Vol 67 (2) ◽

pp. 477-482 ◽

Cited By ~ 33

Author(s):

L. A. Rupp ◽

K. W. Mudge ◽

F. B. Negm

Keyword(s):

Root Growth ◽

Laccaria Laccata ◽

Pinus Mugo ◽

Silver Thiosulfate ◽

Root Branching ◽

Pine Seedlings ◽

Mycorrhiza Formation ◽

Endogenous Ethylene ◽

Ethylene Action

The role of ethylene in mycorrhiza formation and root development on axenically grown seedlings of Pinus mugo Turra var. mugo was examined. Mycorrhizal formation by Laccaria laccata and Pisolithus tinctorius in a defined liquid medium was associated with increased ethylene production. Ethephon (100 μM) stimulated dichotomous branching of roots inoculated with P. tinctorius, but had no effect on those inoculated with L. laccata, or on uninoculated roots. Ethephon had no effect on the percentage of susceptible roots that became mycorrhizal with either fungus. The inhibitor of ethylene action, silver thiosulfate, had no significant effect on mycorrhiza formation by P. tinctorius, but it did show a trend toward decreased mycorrhiza formation by L. laccata when applied at concentrations of 10 μM or higher. Silver thiosulfate at 100 or 500 μM slightly increased dichotomous root branching of seedlings inoculated with either fungus, but these concentrations also caused blackening of root meristems and inhibition of root growth. These results are consistent with the interpretation that endogenous ethylene may influence mycorrhiza formation and associated changes in root morphology.

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Fibrinolytic Activity of Cerebro-Spinal Fluid and the Development of Artificial Cerebral Haematomas in Dogs

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653538 ◽

1969 ◽

Vol 21 (02) ◽

pp. 294-303 ◽

Cited By ~ 3

Author(s):

H Mihara ◽

T Fujii ◽

S Okamoto

Keyword(s):

Cerebrospinal Fluid ◽

Carboxylic Acid ◽

Fibrinolytic Activity ◽

Clinical Implications ◽

Trans Form ◽

Plate Method ◽

Blood Samples ◽

Fibrin Plate ◽

The Brain

SummaryBlood was injected into the brains of dogs to produce artificial haematomas, and paraffin injected to produce intracerebral paraffin masses. Cerebrospinal fluid (CSF) and peripheral blood samples were withdrawn at regular intervals and their fibrinolytic activities estimated by the fibrin plate method. Trans-form aminomethylcyclohexane-carboxylic acid (t-AMCHA) was administered to some individuals. Genera] relationships were found between changes in CSF fibrinolytic activity, area of tissue damage and survival time. t-AMCHA was clearly beneficial to those animals given a programme of administration. Tissue activator was extracted from the brain tissue after death or sacrifice for haematoma examination. The possible role of tissue activator in relation to haematoma development, and clinical implications of the results, are discussed.

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Orphan designation: (6aR,10aR)-3-(1,1-dimethylheptyl)-delta8-tetrahydro-cannabinol-9-carboxylic acid, Treatment of dermatomyositis

Case Medical Research ◽

10.31525/cmr-863651 ◽

2019 ◽

Author(s):

Keyword(s):

Carboxylic Acid ◽

Acid Treatment ◽

Orphan Designation

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Electrochemiluminescence Study of Europium (III) Complex with Coumarin3-Carboxylic Acid

International Journal of Photoenergy ◽

10.1155/2008/131702 ◽

2008 ◽

Vol 2008 ◽

pp. 1-6 ◽

Cited By ~ 9

Author(s):

Stefan Lis ◽

Krzysztof Staninski ◽

Tomasz Grzyb

Keyword(s):

Aqueous Solution ◽

Spectral Analysis ◽

Energy Transfer ◽

Solid State ◽

Carboxylic Acid ◽

Elemental Analysis ◽

Aluminium Electrode ◽

The Eu

The europium (III) complex of coumarin-3-carboxylic acid (C3CA) has been prepared and characterized on the basis of elemental analysis, IR, and emission (photoluminescence and electrochemiluminescence) spectroscopy. The synthesised complex having a formula Eu was photophysically characterized in solution and in the solid state. Electrochemiluminescence, ECL, of the system containing the Eu(III)/C3CA complex was studied using an oxide-covered aluminium electrode. The goal of these studies was to show the possibility of the use of electrochemical excitation of the Eu(III) ion in aqueous solution for emission generation. The generated ECL emission was very weak, and therefore its measurements and spectral analysis were carried out with the use of cut-off filters method. The studies proved a predominate role of the ligand-to-metal energy transfer (LMET) in the generated ECL.

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