Measurements of the Geoelectric Effect in Coleoptiles by a New Technique

Grahm, L.; Hertz, C. H.

doi:10.1111/j.1399-3054.1962.tb07991.x

Cited by 44 publications

(16 citation statements)

References 13 publications

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“…In non-decapitated coleoptiles the geoelectric effect develops rapidly, reaching a maximum value after approximately 30 minutes (2,Woodcock and Wilkins,unpublished). Geotropic curvature, on the other hand, develops much more slowly, especially in coleoptiles grown in red light (7,10), as were those used by Grahm and Hertz (4,5). The difference between the rates of development of the geoelectric effect and the geotropic response could well be accentuated in decapitated coleoptiles which had developed a physiological tip.…”

Section: Methodsmentioning

confidence: 66%

“…The lack of geoelectric effect under anaerobic conditions has also been found by Grahm and Hertz (4) Bearing in mind the consistency between the results in this paper and those of Ball and Dyke (1), Harrison (6) and Wilkins and Warren (9), the fact that we cannot detect a geotropic response in coleoptiles under anaerobic conditions makes it impossible for us to accept the views of Dedolph et al (2) on the lack of a direct relationship between the geoelectric and geotropic responses. There is a large amount of evidence which shows that both phenomena occur as the result of a lateral gradient in auxin concentratioln being set up in the organs (3,4,5,8,11). The finding of Grahm and Hertz (5) that the geoelectric effect develops in Zea coleoptiles after a single decapitation is not evidence for the occurrence of the geoelectric effect in the absence of auxin.…”

Section: Methodsmentioning

confidence: 85%

See 1 more Smart Citation

Geotropic Response of Coleoptiles under Anaerobic Conditions¹

Wilkins¹,

Shaw²

1967

Plant Physiol.

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Section: Methodsmentioning

confidence: 66%

Section: Methodsmentioning

confidence: 85%

Geotropic Response of Coleoptiles under Anaerobic Conditions¹

Wilkins¹,

Shaw²

1967

Plant Physiol.

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“…Epinasty of branches was first reported in 1872 by De Vries (3) and confirmed by Baranetzsky (1) (8).…”

mentioning

confidence: 76%

Auxin Factor in Branch Epinasty

Lyon

1963

Plant Physiol.

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“…When several such spectra were produced (38,143) and showed peaks at 370 nm, the argument for flavin photoreception was strengthened considerably. But, it was argued that certain cis-carotenoids would be expected to have significant peaks near 370 nm (144), and the later demonstration that carotenoids dissolved in polar solvents develop considerable absorbance near 360 nm (64) (61,62) show that decapitated, auxin-starved coleoptiles do not develop such a transverse potential unless auxin is administered. From comparisons with careful kinetic studies of the movement of labeled IAA, it appears that lateral displacement of auxin occurs before the potential appears; thus, the potential is a result rather than a cause of auxin asymmetry.…”

Section: Tirelymentioning

confidence: 99%

Plant Photobiology in the Last Half-Century

Galston

1974

Plant Physiol.

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The absorption of light energy not only nourishes the plant through photosynthetic phosphorylation and concomitant carbon dioxide fixation, but it also determines the nature and the direction of plant growth. This review will summarize the major advances in the physiology of both of the latter processes over the last half-century. Because of severe limitations of space, only a few key concepts can be mentioned, let alone emphasized, and some fields, like algal phototaxis, must be omitted entirely.Although there was certainly provocative earlier work by Klebs and others (100) (49,144). Although a definite conclusion cannot yet be made, the bulk of recent evidence favors the flavin hypothesis. I shall try to summarize this evidence and certain other aspects of the physiology of phototropism as well. Although experimentation in phototropism has been relatively quiescent for about 20 years, recent developments provide encouragement for new insights into this process.Some methodological problems are unique to this kind of biology. Decisions about photoreceptor pigments depend on correlations between action spectra for the process and absorption spectra for the pigment (10,160). Light, to be effective, must first be absorbed, and in energy ranges where photon absorption limits the rate or extent of a process, there should be rough correspondence between regions of the spectrum that are most active in eliciting a process and regions of high light absorption by the pigment. One cannot push these coincidences too far, however, because other pigments can act as light screens, differential refraction of different wavelengths inside the tissue can produce distortion in relative actinic effectiveness, attachment of pigments to different proteins can 1 Dedicated to the memory of Harry A. Borthwick, a wise and compassionate man. Generous support from the National Science Foundation has made possible the author's active involvement in this field for more than 20 years. alter their absorption properties in different ways, resonance transfer of energy between pigments or unequal quantum efficiencies at different wavelengths can alter curves, and dichroic orientation of a pigment in a lamella may produce aberrant or unrepresentative values. Despite these caveats, action spectra remain the major method for inferring the nature of the photoreceptor (130,131).Action spectra are prepared by doing dose-response energy experiments at each of the wavelengths employed. From such data, provided that the reciprocity law holds, one can calculate the energy required to produce a standard effect, e.g. 50% promotion of seed germination. When corrected for the different energy of quanta in the different portions of the spectrum and transformed to reciprocal values, these data tell us the relative effectiveness of quanta in producing the observed physiological effect. A plot of this parameter against wavelength gives the standard action spectrum.Deducing the nature of the photoreceptor pigment is only the first step along the difficult road of ...

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Measurements of the Geoelectric Effect in Coleoptiles by a New Technique

Cited by 44 publications

References 13 publications

Geotropic Response of Coleoptiles under Anaerobic Conditions¹

Geotropic Response of Coleoptiles under Anaerobic Conditions¹

Auxin Factor in Branch Epinasty

Plant Photobiology in the Last Half-Century

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Measurements of the Geoelectric Effect in Coleoptiles by a New Technique

Cited by 44 publications

References 13 publications

Geotropic Response of Coleoptiles under Anaerobic Conditions1

Geotropic Response of Coleoptiles under Anaerobic Conditions1

Auxin Factor in Branch Epinasty

Plant Photobiology in the Last Half-Century

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Geotropic Response of Coleoptiles under Anaerobic Conditions¹

Geotropic Response of Coleoptiles under Anaerobic Conditions¹