A reduced xylem pressure altered the electric and growth responses in cucumber hypocotyls

Stahlberg, Rainer; Cosgrove, Daniel J.

doi:10.1046/j.1365-3040.1997.d01-7.x

Cited by 9 publications

(14 citation statements)

References 41 publications

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“…Several hypotheses are currently considered in the literature (Malone & Alarcon 1995): phloem transport of proteinase-inhibitor inducing factors (PIIF; Pearce et al 1991), hydraulic dispersal of PIIF chemicals by mass flow in the xylem (Malone 1993(Malone , 1994, and electrical transmission (Williams & Pickard 1972;Roblin & Bonnemain 1979, 1985Satter 1990;Fromm 1991;Sibaoka 1991;Wildon et al 1992). Our results suggest that (1) an intricate relationship between electrical and hydraulic signals frequently exists (see also Malone & Stankovic 1991;Stahlberg & Cosgrove 1997) and that (2) other mechanisms for transmission of electrical signals must be taken into consideration.…”

Section: Discussionmentioning

confidence: 70%

“…However, it can be argued that these changes did not reflect the occurrence of streaming potentials, but rather changes in the membrane potentials of root cells generated by osmotically induced changes of the turgor pressure of these cells. Turgor pressure-dependent transport processes in the plasmalemma membrane of algae and higher plants are well known (Zimmermann & Steudle 1974;Zimmermann & Beckers 1977;Wendler, Zimmermann & Bentrup 1983;Stahlberg & Cosgrove 1997;Lew 1996).…”

Section: Discussionmentioning

confidence: 99%

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Simultaneous recording of xylem pressure and trans‐root potential in roots of intact glycophytes using a novel xylem pressure probe technique

Wegner

Zimmermann

1998

Plant Cell & Environment

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The radial electrical potential difference between the root xylem and the bathing solution, i.e. the so-called trans-root potential, was measured in intact maize and wheat plants using a xylem pressure probe into which an Ag/AgCl electrode was incorporated. Besides other advantages (e.g. detection and removal of tip clogging; determination of the radial root resistance), the novel probe allowed placement of the electrode precisely in a single xylem vessel as indicated by the reading of sub-atmospheric or negative pressure values upon penetration. The trans-root potentials were of the order of 0 to -70 mV and + 40 to -20 mV for 2-to 3-week-old maize and wheat plants, respectively. Osmotic experiments performed on maize demonstrated that addition of 100 mM mannitol to the solution resulted in a decrease of xylem pressure associated with a slow, but continuous depolarization. The depolarization was reversible upon removal of the mannitol. For wheat plants it could be shown that the oscillations of the xylem pressure described recently by Schneider et al. (1997, Plant, Cell and Environment 20, 221-229) were accompanied by (rectangular, saw-tooth and/or U-shaped) oscillations in the trans-root potential (but not by corresponding changes of the membrane potential of the cortical cells measured simultaneously with conventional microelectrodes). Increase of the light intensity (up to 550 µmol m -2 s -1 ) resulted in a drop of the xylem pressure in wheat, whereas the trans-root potential showed a biphasic response: first hyperpolarization (by about 10 mV) was observed, followed by depolarization (by up to about + 40 mV). Similar light-induced biphasic (but often less pronounced) changes in the trans-root potential were also recorded for maize plants. Most interestingly, the response of the trans-root potential was always faster (by about 1-3 min) than the response of the xylem pressure upon illumination, suggesting that changes in the transpiration rate are reflected very quickly in the electrical properties of the root tissue. The impact of this and other findings on long-distance transport of solutes and water as well as on long-distance signalling is discussed. Key-words:Poaceae; Triticum aestivum L. cv. Alexandria; wheat; Zea mays L. cv. Zelltic; maize; electrokinetic effects, pressure-potential probe; trans-root potential (TRP); xylem pressure. INTRODUCTIONMeasurements of the electrical potential difference between the solution bathing the root and the xylem, i.e. the so-called trans-root potential, provide a way to elucidate the contribution of electrical forces to solute and water transport through the root (Etherton & Higinbotham 1960;Bowling & Spanswick 1964;Shone 1969;Davis & Higinbotham 1969;Läuchli, Spurr & Epstein 1971;Cortes 1992;Rygol et al. 1993;Clarkson 1993;Marschner 1995). Reliable data on these forces and their coupling to transpiration-induced changes in xylem pressure, and to turgor pressure of the hydraulically coupled root cells (Andrews 1976;Stahlberg & Cosgrove 1995;Schneider, Zhu & Zimm...

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Section: Discussionmentioning

confidence: 70%

Section: Discussionmentioning

confidence: 99%

Simultaneous recording of xylem pressure and trans‐root potential in roots of intact glycophytes using a novel xylem pressure probe technique

Wegner

Zimmermann

1998

Plant Cell & Environment

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“…This transient growth response is a direet hydraulic effect of the sitnultaneously occurring P^ ehange and is likely to reflect a rapid response of the hypoeotyl cells to a temporarily reduced turgor pressure (see Stahlberg & Cosgrove 1994, 1995, 1997a. Slow P^ ehanges (by the inhibition of active transport) failed to cause this rapid GR response, showing that it is not a general response of the hypocotyl GR to P^ reduction.…”

Section: Discussionmentioning

confidence: 99%

“…9 eotnpared with Eig. 6) and was followed by a transient rise in GR whieh has been analysed before (Stahlberg & Cosgrove 1994, 1997a. A sustained reduction in the hypocotyl GR occurred after about 30 min.…”

Section: What Is the Typical Growth Response Of Cucumber Hypoeotyls Tmentioning

confidence: 99%

Mannitol inhibits growth of intact cucumber but not pea seedlings by mechanically collapsing the root pressure

Stahlberg

Cosgrove

1997

Plant Cell & Environment

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The positive xylem pressure (P^) in cucumber hypoeotyls is a direct extension of root pressure and therefore depends on the root environment. Solutions of the electrolyte KCl (0-10 osm) reduced the hypocotyl P,^ transiently (biphasic response), while the P^ reduction by mannitol solutions was sustained. The amplitudes of the induced P^ reduction depeuded directly, and the degree of Px restoration after stress release depended indirectly, on the size of the initial positive P^, indicating that mannitol released the root pressure by a mechanical rather than osmotic mechanism. Mannitol treatment and other means of root pressure reduction revealed two separate growth responses in the affected cucumber hypoeotyls. Only steep Px drops (following root excision or root pressure release in mannitol) directly cause a rapid, transient drop in gro\yth rate (GR). Both rapid and slow (after root incubation in KCN or NEM) decreases in root pressure, however, led to a sustained growth inhibition of cucumber hypoeotyls after about 30niin. This delay characterizes the growth response as an indirect consequence of the Pĉ hange. Pea seedlings, which lacked root pressure and had a negative P^ throughout, showed extremely small changes in epicotyl P^ and GR after root incubation in mannitol. It is apparent that the higher sensitivity of cucumber growth to mannitol depended on the presence and release of root pressure.

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“…Different from the animal electrical signal, plant electrical signal is induced by a change of environment factors (such as temperature, light, water, etc.) [27][28][29][30][31][32][33][34]. In general, when the environment is in steady state, the electrical signal response will not occur except for imposing external stimuli.…”

Section: Introductionmentioning

confidence: 99%

Plant Electrical Signal Classification Based on Waveform Similarity

et al. 2016

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(1) Background: Plant electrical signals are important physiological traits which reflect plant physiological state. As a kind of phenotypic data, plant action potential (AP) evoked by external stimuli-e.g., electrical stimulation, environmental stress-may be associated with inhibition of gene expression related to stress tolerance. However, plant AP is a response to environment changes and full of variability. It is an aperiodic signal with refractory period, discontinuity, noise, and artifacts. In consequence, there are still challenges to automatically recognize and classify plant AP; (2) Methods: Therefore, we proposed an AP recognition algorithm based on dynamic difference threshold to extract all waveforms similar to AP. Next, an incremental template matching algorithm was used to classify the AP and non-AP waveforms; (3) Results: Experiment results indicated that the template matching algorithm achieved a classification rate of 96.0%, and it was superior to backpropagation artificial neural networks (BP-ANNs), supported vector machine (SVM) and deep learning method; (4) Conclusion: These findings imply that the proposed methods are likely to expand possibilities for rapidly recognizing and classifying plant action potentials in the database in the future.

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A reduced xylem pressure altered the electric and growth responses in cucumber hypocotyls

Cited by 9 publications

References 41 publications

Simultaneous recording of xylem pressure and trans‐root potential in roots of intact glycophytes using a novel xylem pressure probe technique

Simultaneous recording of xylem pressure and trans‐root potential in roots of intact glycophytes using a novel xylem pressure probe technique

Mannitol inhibits growth of intact cucumber but not pea seedlings by mechanically collapsing the root pressure

Plant Electrical Signal Classification Based on Waveform Similarity

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