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Electrical signals in prayer plants (marantaceae)? Insights into the trigger mechanism of the explosive style movement.

Jerominek M, Claßen-Bockhoff R - PLoS ONE (2015)

Bottom Line: In both species, chemical and electric stimulations do not release the style movement.It is concluded that the style movement in Marantaceae is released mechanically by relieving the tissue pressure.Accordingly, the variation potential is an effect of the movement and not its cause.

View Article: PubMed Central - PubMed

Affiliation: Institut für Spezielle Botanik und Botanischer Garten, Johannes Gutenberg-Universität, Mainz, Germany.

ABSTRACT
The explosive pollination mechanism of the prayer plants (Marantaceae) is unique among plants. After a tactile stimulus by a pollinator, the style curls up rapidly and mediates pollen exchange. It is still under discussion whether this explosive movement is released electrophysiologically, i.e. by a change in the membrane potential (as in Venus flytrap), or purely mechanically. In the present study, electrophysiological experiments are conducted to clarify the mechanism. Artificial release experiments (chemical and electrical) and electrophysiological measurements were conducted with two phylogenetically distant species, Goeppertia bachemiana (E. Morren) Borchs. & S. Suárez and Donax canniformis (G. Forst.) K. Schum. Electric responses recorded after style release by extracellular measurements are characterised as variation potentials due to their long repolarization phase and lack of self-perpetuation. In both species, chemical and electric stimulations do not release the style movement. It is concluded that the style movement in Marantaceae is released mechanically by relieving the tissue pressure. Accordingly, the variation potential is an effect of the movement and not its cause. The study exemplarily shows that fast movements in plants are not necessarily initiated by electric changes of the membrane as known from the Venus flytrap.

No MeSH data available.


Amplitudes of the extracellular measurements.Style released by artificially deflecting the trigger appendage (A, B) or by applying a chloroform droplet (C) in Donax canniformis and Goeppertia bachemiana. The left border of the time bar (20 s) indicates the stimulus (to); black arrows, apoplastic voltage change after 0.5 s; white arrow, pre-peak (only observed in chemical experiments). In C the style is released after the pre-peak drops, the corresponding ΔV-value was corrected (dotted line).
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pone.0126411.g005: Amplitudes of the extracellular measurements.Style released by artificially deflecting the trigger appendage (A, B) or by applying a chloroform droplet (C) in Donax canniformis and Goeppertia bachemiana. The left border of the time bar (20 s) indicates the stimulus (to); black arrows, apoplastic voltage change after 0.5 s; white arrow, pre-peak (only observed in chemical experiments). In C the style is released after the pre-peak drops, the corresponding ΔV-value was corrected (dotted line).

Mentions: After the artificial deflection of the trigger appendage, the styles of both species show electric responses immediately (Fig 5, S1 Video). The apoplast usually hyperpolarized (Fig 5) except for few cases of depolarization. The amplitude was variable. There was either a distinct peak which directly declined indicating repolarization (Fig 5B) or a steep increase which was followed by a gradual rise and a delayed decline (Fig 5A, S1 Video). To nevertheless compare the data, the ΔV-values were always measured 0.5 s after style release.


Electrical signals in prayer plants (marantaceae)? Insights into the trigger mechanism of the explosive style movement.

Jerominek M, Claßen-Bockhoff R - PLoS ONE (2015)

Amplitudes of the extracellular measurements.Style released by artificially deflecting the trigger appendage (A, B) or by applying a chloroform droplet (C) in Donax canniformis and Goeppertia bachemiana. The left border of the time bar (20 s) indicates the stimulus (to); black arrows, apoplastic voltage change after 0.5 s; white arrow, pre-peak (only observed in chemical experiments). In C the style is released after the pre-peak drops, the corresponding ΔV-value was corrected (dotted line).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440630&req=5

pone.0126411.g005: Amplitudes of the extracellular measurements.Style released by artificially deflecting the trigger appendage (A, B) or by applying a chloroform droplet (C) in Donax canniformis and Goeppertia bachemiana. The left border of the time bar (20 s) indicates the stimulus (to); black arrows, apoplastic voltage change after 0.5 s; white arrow, pre-peak (only observed in chemical experiments). In C the style is released after the pre-peak drops, the corresponding ΔV-value was corrected (dotted line).
Mentions: After the artificial deflection of the trigger appendage, the styles of both species show electric responses immediately (Fig 5, S1 Video). The apoplast usually hyperpolarized (Fig 5) except for few cases of depolarization. The amplitude was variable. There was either a distinct peak which directly declined indicating repolarization (Fig 5B) or a steep increase which was followed by a gradual rise and a delayed decline (Fig 5A, S1 Video). To nevertheless compare the data, the ΔV-values were always measured 0.5 s after style release.

Bottom Line: In both species, chemical and electric stimulations do not release the style movement.It is concluded that the style movement in Marantaceae is released mechanically by relieving the tissue pressure.Accordingly, the variation potential is an effect of the movement and not its cause.

View Article: PubMed Central - PubMed

Affiliation: Institut für Spezielle Botanik und Botanischer Garten, Johannes Gutenberg-Universität, Mainz, Germany.

ABSTRACT
The explosive pollination mechanism of the prayer plants (Marantaceae) is unique among plants. After a tactile stimulus by a pollinator, the style curls up rapidly and mediates pollen exchange. It is still under discussion whether this explosive movement is released electrophysiologically, i.e. by a change in the membrane potential (as in Venus flytrap), or purely mechanically. In the present study, electrophysiological experiments are conducted to clarify the mechanism. Artificial release experiments (chemical and electrical) and electrophysiological measurements were conducted with two phylogenetically distant species, Goeppertia bachemiana (E. Morren) Borchs. & S. Suárez and Donax canniformis (G. Forst.) K. Schum. Electric responses recorded after style release by extracellular measurements are characterised as variation potentials due to their long repolarization phase and lack of self-perpetuation. In both species, chemical and electric stimulations do not release the style movement. It is concluded that the style movement in Marantaceae is released mechanically by relieving the tissue pressure. Accordingly, the variation potential is an effect of the movement and not its cause. The study exemplarily shows that fast movements in plants are not necessarily initiated by electric changes of the membrane as known from the Venus flytrap.

No MeSH data available.