Propagated fluctuations of the electric potential in the apoplasm of Lepidium sativum L. roots

Hejnowicz, Z.; Krause, E.; Głębicki, Krzysztof; Sievers, Andreas

doi:10.1007/bf00201508

Cited by 18 publications

(6 citation statements)

References 25 publications

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“…To our knowledge, the only published article reporting electrical events spontaneously generated in roots was published by Hejnowicz et al (52). In their article, a basipetal propagation of the signals for short distances (1.3 mm) and with a conduction velocity of 3-9 mm⅐s Ϫ1 was reported.…”

Section: Discussionmentioning

confidence: 99%

Spatiotemporal dynamics of the electrical network activity in the root apex

Masi

Ciszak

Stefano

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

126

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Section: Discussionmentioning

confidence: 99%

Spatiotemporal dynamics of the electrical network activity in the root apex

Masi

Ciszak

Stefano

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

126

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“…The rapidity of this response suggests the possibility of direct gravisensing by these cells, although rapid (electrical? ± see Hejnowicz et al 1991) transmission of a signal from the cap to the DEZ is also possible.…”

Section: Site Of Graviperceptionmentioning

confidence: 99%

Cellular specifiCity of the gravitropic motor response in roots

Evans

Ishikawa

1997

Planta

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A number of features of the gravitropic response of roots are not readily accounted for by the classical Cholodny-Went theory. These include the observations that (i) in the later stages of the response the growth gradient is reversed with no evident reversal of the auxin gradient; (ii) a major component of the acceleration of growth along the upper side occurs in the distal elongation zone (DEZ), a group of cells located between the meristem and the main elongation, not within the central elongation zone; and (iii) the initiation of differential growth in the DEZ appears to be independent of the establishment of auxin asymmetry. Alternative candidates for mediation of differential growth in the DEZ include calcium ions and protons. Gravi-induced curvature is accompanied by polar movement of calcium toward the lower side of the maize root tip and the DEZ is shown to be particularly sensitive to growth inhibition by calcium. Also, gravistimulation of maize roots causes enhanced acid efflux from the upper side of the DEZ. Evidence for gravi-induced modification of ion movements in the root tip includes changes in intracellular potentials and current flow. It is clear that there is more than one motor region in the root with regard to gravitropic responses and there is evidence that the DEZ itself consists of more than one class of responding cells. In order to gain a more complete understanding of the mechanism of gravitropic curvature, the physiological properties of the sub-zones of the root apex need to be thoroughly characterized with regard to their sensitivity to hormones, calcium, acid pH and electrical perturbations.

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“…However, there is no indication of long-distance transmission of electrical signals in root tips either via action potentials or through electrotonic (i.e. passive) propagation ; but see Hejnowicz et al 1991 for a proposed signaling pathway along an intrasymplasmic continuous system composed of ER and desmotubules) and no evidence for gravi-induced electrical changes independent of the root cap (Monshausen et al 1996), and so the identity of the signal remains elusive.…”

Section: Introductionmentioning

confidence: 99%

Basipetal propagation of gravity-induced surface pH changes along primary roots of Lepidium sativum L.

Monshausen

Sievers

2002

Planta

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While there is ample evidence for a role of auxin in root gravitropism, the seeming rapidity of gravi-induced changes in electrical parameters has so far been an argument against auxin being a primary signal in gravitropic signal transmission. To address this problem, we re-investigated the effect of gravistimulation on membrane voltages of Lepidium sativum L. and Vigna mungo L. root cells. In our hands, gravistimulation did not induce changes in membrane voltage in cells of the root cap statenchyma, root meristem or apical elongation zone that can be correlated with the orientation of the cells relative to the gravity vector. While these results challenge a model of rapid electrically based signal transmission, there is evidence for a slower signal propagation along gravistimulated L. sativum roots. Using multiple proton-selective microelectrodes to simultaneously measure surface pH on opposite root flanks at different distances from the root tip, we observed gravi-induced asymmetric pH changes at the surface of all investigated root zones. Upon gravistimulation, the surface pH decreased on the physically upper root flank and increased on the lower flank. The pH asymmetry appeared first [2.1+/-0.4 min (mean +/- SD) after tilting] at the root cap and then - with incrementing lag times - at the meristem (after 2.5+/-0.3 min at 300 micro m from root tip; after 3.7+/-0.4 min at 700 micro m) and apical elongation zone (4.8+/-0.5 min at 1,000 micro m), suggesting a basipetal progression of differential surface acidification at a rate of 250-350 micro m min(-1), consistent with reported auxin transport rates.

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Propagated fluctuations of the electric potential in the apoplasm of Lepidium sativum L. roots

Cited by 18 publications

References 25 publications

Spatiotemporal dynamics of the electrical network activity in the root apex

Spatiotemporal dynamics of the electrical network activity in the root apex

Cellular specifiCity of the gravitropic motor response in roots

Basipetal propagation of gravity-induced surface pH changes along primary roots of Lepidium sativum L.

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