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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.


Related in: MedlinePlus

Experimental design for the extracellular measurements.The reference electrode (re) is positioned in an acrylic glass chamber through a small lateral hole. The fixed flowers were placed in water and the electrical change is measured using a microelectrode (me). (A) mechanical stimulation by deflecting the trigger appendage using a glass tube. (B) chemical stimulation by applying a droplet of chloroform with a syringe to the basal plate. (C) negative control experiment with an inhibited trigger appendage (basal plate is lifted, see arrow); the style is released by removing the hood with a class tube. (D) electrical stimulation, given via a minutien needle to test whether the style can be released electrically. (E) chemical stimulus by applying chloroform with a microelectrode to the style surface. (F) positive control; testing the electrophysiological equipment with a dissected leaf of Dionaea muscipula.
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pone.0126411.g003: Experimental design for the extracellular measurements.The reference electrode (re) is positioned in an acrylic glass chamber through a small lateral hole. The fixed flowers were placed in water and the electrical change is measured using a microelectrode (me). (A) mechanical stimulation by deflecting the trigger appendage using a glass tube. (B) chemical stimulation by applying a droplet of chloroform with a syringe to the basal plate. (C) negative control experiment with an inhibited trigger appendage (basal plate is lifted, see arrow); the style is released by removing the hood with a class tube. (D) electrical stimulation, given via a minutien needle to test whether the style can be released electrically. (E) chemical stimulus by applying chloroform with a microelectrode to the style surface. (F) positive control; testing the electrophysiological equipment with a dissected leaf of Dionaea muscipula.

Mentions: Fresh flowers were collected in the Botanical Gardens at Mainz (Donax canniformis) and Gießen (Goeppertia bachemiana). There is no specific permission required for these locations/activities since the material belongs to an old botanical collection. Corresponding to the ‘IUCN Red List’ both species are not endangered or protected. In view of the rapid wilting process, all flowers were picked in a fresh stage (the latest 6 h after the beginning of anthesis) and examined in the laboratory. Flowers were stored in a plastic box on wet tissue to keep them fresh (for max. 2 h). They were cut above the ovary and dissected to uncover style and hooded staminode. This functional unit was then fixed in a custom-made acrylic glass chamber (Fig 3) by using plasticine.


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

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

Experimental design for the extracellular measurements.The reference electrode (re) is positioned in an acrylic glass chamber through a small lateral hole. The fixed flowers were placed in water and the electrical change is measured using a microelectrode (me). (A) mechanical stimulation by deflecting the trigger appendage using a glass tube. (B) chemical stimulation by applying a droplet of chloroform with a syringe to the basal plate. (C) negative control experiment with an inhibited trigger appendage (basal plate is lifted, see arrow); the style is released by removing the hood with a class tube. (D) electrical stimulation, given via a minutien needle to test whether the style can be released electrically. (E) chemical stimulus by applying chloroform with a microelectrode to the style surface. (F) positive control; testing the electrophysiological equipment with a dissected leaf of Dionaea muscipula.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0126411.g003: Experimental design for the extracellular measurements.The reference electrode (re) is positioned in an acrylic glass chamber through a small lateral hole. The fixed flowers were placed in water and the electrical change is measured using a microelectrode (me). (A) mechanical stimulation by deflecting the trigger appendage using a glass tube. (B) chemical stimulation by applying a droplet of chloroform with a syringe to the basal plate. (C) negative control experiment with an inhibited trigger appendage (basal plate is lifted, see arrow); the style is released by removing the hood with a class tube. (D) electrical stimulation, given via a minutien needle to test whether the style can be released electrically. (E) chemical stimulus by applying chloroform with a microelectrode to the style surface. (F) positive control; testing the electrophysiological equipment with a dissected leaf of Dionaea muscipula.
Mentions: Fresh flowers were collected in the Botanical Gardens at Mainz (Donax canniformis) and Gießen (Goeppertia bachemiana). There is no specific permission required for these locations/activities since the material belongs to an old botanical collection. Corresponding to the ‘IUCN Red List’ both species are not endangered or protected. In view of the rapid wilting process, all flowers were picked in a fresh stage (the latest 6 h after the beginning of anthesis) and examined in the laboratory. Flowers were stored in a plastic box on wet tissue to keep them fresh (for max. 2 h). They were cut above the ovary and dissected to uncover style and hooded staminode. This functional unit was then fixed in a custom-made acrylic glass chamber (Fig 3) by using plasticine.

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.


Related in: MedlinePlus