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1.
Electrical signaling and rapid closure of the carnivorous plant Dionaea muscipula Ellis (Venus flytrap) have been attracting the attention of researchers since XIX century, but the exact mechanism of Venus flytrap closure is still unknown. We found that the electrical stimulus between a midrib and a lobe closes the Venus flytrap leaf by activating motor cells without mechanical stimulation of trigger hairs. The closing time of Venus flytrap by electrical stimulation of motor cells is 0.3 s, the same as mechanically induced closing. The mean electrical charge required for the closure of the Venus flytrap leaf is 13.6 µC. Ion channel blockers such as Ba2+, TEACl as well as uncouplers such as FCCP, 2,4-dinitrophenol and pentachlorophenol dramatically decrease the speed of the trap closing. Using an ultra-fast data acquisition system with measurements in real time, we found that the action potential in the Venus flytrap has a duration time of about 1.5 ms. Our results demonstrate that electrical stimulation can be used to study mechanisms of fast activity in motor cells of the plant kingdom.Key Words: action potential, electrophysiology, electrical signaling, Venus flytrap, motor cells 相似文献
2.
Alexander G. Volkov Chrystelle L. Vilfranc Veronica A. Murphy Colee M. Mitchell Maia I. Volkova Lawrence O’Neal Vladislav S. Markin 《Journal of plant physiology》2013
The electrical phenomena and morphing structures in the Venus flytrap have attracted researchers since the nineteenth century. We have observed that mechanical stimulation of trigger hairs on the lobes of the Venus flytrap induces electrotonic potentials in the lower leaf. Electrostimulation of electrical circuits in the Venus flytrap can induce electrotonic potentials propagating along the upper and lower leaves. The instantaneous increase or decrease in voltage of stimulating potential generates a nonlinear electrical response in plant tissues. Any electrostimulation that is not instantaneous, such as sinusoidal or triangular functions, results in linear responses in the form of small electrotonic potentials. The amplitude and sign of electrotonic potentials depend on the polarity and the amplitude of the applied voltage. Electrical stimulation of the lower leaf induces electrical signals, which resemble action potentials, in the trap between the lobes and the midrib. The trap closes if the stimulating voltage is above the threshold level of 4.4 V. Electrical responses in the Venus flytrap were analyzed and reproduced in the discrete electrical circuit. The information gained from this study can be used to elucidate the coupling of intracellular and intercellular communications in the form of electrical signals within plants. 相似文献
3.
The Venus flytrap is the most famous carnivorous plant. The electrical stimulus between a midrib and a lobe closes the Venus flytrap upper leaf in 0.3 s without mechanical stimulation of trigger hairs. Here we present results for direct measurements of the closing force of the trap of Dionaea muscipula Ellis after mechanical or electrical stimulation of the trap using the piezoelectric thin film or Fuji Prescale indicating sensor film. The closing force was 0.14 N and the corresponding pressure between rims of two lobes was 38 kPa. We evaluated theoretically using the Hydroelastic Curvature Model and compared with experimental data velocity, acceleration and kinetic energy from the time dependencies of distance between rims of lobes during the trap closing. The Charge Stimulation Method was used for trap electrostimulation between the midrib and lobes. From the dependence of voltage between two Ag/AgCl electrodes in the midrib and one of the lobes, we estimated electrical charge, current, resistance, electrical energy and electrical power dependencies on time during electrostimulation of the trap. 相似文献
4.
Kinetics and mechanism of Dionaea muscipula trap closing 总被引:1,自引:0,他引:1
5.
Alexander G. Volkov Monique-Renée PinnockDennell C. Lowe Ma’Resha S. GayVladislav S. Markin 《Journal of plant physiology》2011,168(2):109-120
The total hunting cycle of the Venus flytrap consists of five stages: 1. Open state → 2. Closed state → 3. Locked state → 4. Constriction and digestion → 5. Semi-open state → 1. Open state. The opening of the trap after digestion consists of two steps: opening of the lobes, and changing of their curvature from concave to convex shape. Uncouplers carbonylcyanide-4-trifluoromethoxyphenyl hydrazone (FCCP) and carbonylcyanide-3-chlorophenylhydrazone (CCCP) inhibit the trap from opening for two weeks and antracene-9-carboxylic acid inhibits the trap from constricting. Different stages of the hunting cycle have different electrical characteristics. The biologically closed electrochemical circuits in the Venus flytrap are analyzed using the charged capacitor method. If the initial voltage applied to the Venus flytrap is 0.5 V or greater, changing the polarity of the electrodes between the midrib and one of the lobes results in a rectification effect and in different kinetics of discharge capacitance. These effects can be caused by the fast transport of ions through ion channels. The electrical properties of the Venus flytrap were investigated and equivalent electrical circuits within the upper leaf were proposed to explain the experimental data. 相似文献
6.
Alexander G Volkov Holly Carrell Tejumade Adesina Vladislav S Markin Emil Jovanov 《Plant signaling & behavior》2008,3(7):490-492
Electrical signaling, short-term memory and rapid closure of the carnivorous plant Dionaea muscipula Ellis (Venus flytrap) have been attracting the attention of researchers since the XIX century. We found that the electrical stimulus between a midrib and a lobe closes the Venus flytrap upper leaf without mechanical stimulation of trigger hairs. The closing time of Venus flytrap by electrical stimulation is the same as mechanically induced closing. Transmission of a single electrical charge between a lobe and the midrib causes closure of the trap and induces an electrical signal propagating between both lobes and midrib. The Venus flytrap can accumulate small subthreshold charges, and when the threshold value is reached, the trap closes. Repeated application of smaller charges demonstrates the summation of stimuli. The cumulative character of electrical stimuli points to the existence of short-term electrical memory in the Venus flytrap.Key words: plant memory, electrophysiology, electrical signaling, venus flytrap, Dionaea muscipula ellisPlants are capable of intelligent responses to complex environmental signals.1–27 Signaling and memory play fundamental roles in plant responses. The existence of different forms of plant memory is well known.1–22 Depending on the duration of memory retention, there are three types of memory in plants: sensory memory, short term memory and long term memory. A few examples of studies involving plant memory are: transgeneration memory of stress,1,6,10 immunological memory of tobacco plants22 and mountain birches,18 storage and recall functions in seedlings,9 chromatin remodelling in plant development,4,19 vernalization and epigenetic memory of winter,12,13 induced resistance and susceptibility to herbivory,2 memory response in ABA-entrained plants,6 memory of stimulus,16,17 and systematic acquired resistance in plants exposed to a pathogen.22 Cellular memory is an example of long term memory and is a long-term maintenance of a particular pattern of gene expression. Chromatin dynamics including histone modification, histone replacement and chromatin remodeling play key roles in cellular memory.4 Plants are intelligent organisms and capable of functions such as learning, individuality, plasticity and memory.5 There are a few mathematical models of plant learning and memory.14,15 Some plants exhibit clues of an electrical memory as well.We found that Venus flytrap has a short term electrical memory20,21 Rapid closure of the carnivorous plant Dionaea muscipula Ellis (Venus flytrap) has been attracting the attention of researchers and as a result its mechanism has been widely investigated. When an insect touches the trigger hairs, these mechanosensors generate an electrical signal that acts as an action potential, which activates the trap closing. Macfarlane23 found that two mechanical stimuli required for the trap closing should be applied within an interval from 0.75 s to 20 s. Brown and Sharp24 found that at high temperature of 35–40°C usually only one mechanical stimulus is required.The inducement of non-excitability after excitation and the summation of subthreshold irritations were developed in the vegetative and animal kingdoms in protoplasmic structures prior to morphological differentiation of nervous tissues. These protoplasmic structures merged into the organs of a nervous system and adjusted the interfacing of the organism with the environment. Some neuromotoric components include acetylcholine neurotransmitters, cellular messenger calmodulin, cellular motors actin and myosin, voltage-gated channels, and sensors for touch, light, gravity and temperature.25–27 Although this nerve-like cellular equipment has not reached the same great complexity as in animal nerves, a simple neural network has been formed within the plasma membrane of a phloem or plasmodesmata enabling it to communicate efficiently over long distances.5,26,27 The reason why plants have developed pathways for electrical signal transmission most probably lies in the necessity to respond rapidly to environmental stress factors. Different environmental stimuli evoke specific responses in living cells, which have the capacity to transmit a signal to the responding region. In contrast to chemical signals such as hormones, electrical signals are able to rapidly transmit information over long distances.27 Electrical potentials have been measured at the tissue and whole plant levels.26Using our new charge injection method,20 it was evident that the application of an electrical stimulus between the midrib (positive potential) and a lobe (negative potential) causes Venus flytrap to close the trap without any mechanical stimulation. The average stimulation pulse voltage sufficient for rapid closure of the Venus flytrap was 1.50 V (standard deviation is 0.01 V, n = 50) for 1 s. The inverted polarity pulse with negative voltage applied to the midrib did not close the plant. Applying impulses in the same voltage range with different polarities for pulses of up to 100 s did not open the plant. It was found that energy for trap closure is generated by ATP hydrolysis. ATP is used by the motor cells for a fast transport of protons. The amount of ATP drops from 950 µM per midrib before mechanical stimulation to 650 µM per midrib after stimulation and closure.28 However, it is not clear if electrical stimulation triggers closing process in the motor cells, or contributes energy to the closing action.The action potential delivers sufficient electrical charge to the midrib,21 which can activate the osmotic motor. To check this hypothesis, we measured effects of transmitted charge from the charged capacitors between the lobe and the midrib of Venus flytrap. Transmission of a single electrical charge (mean 13.63 µC, median 14.00 µC, std. dev. 1.51 µC, n = 41) causes trap closure and induces an electrical signal propagating between the lobes and the midrib. The electrical signal in the lobes was not an action potential, because its amplitude depended on the applied voltage from the charged capacitor. Charge induced closing of a trap plant can be repeated 2–3 times on the same Venus flytrap plant after reopening. Transmission of a single electrical charge (mean 13.63 µC, median 14.00 µC, std. dev. 1.51 µC, n = 41) causes the trap to close and induces an electrical signal that propagates between the lobe and the midrib. Figure 1 illustrates that the Venus flytrap can accumulate small charges, and when the threshold value is reached, the trap closes. A summation of stimuli is demonstrated through the repetitive application of smaller charges. If we apply two or more consecutive injections of electrical charge within a period of less than 50 s, the trap will close when a total of 14 µC charge is reached.Open in a separate windowFigure 1Mechanism of the Dionaea trap closure.Repeated application of smaller charges demonstrates a summation of stimuli. If we apply two or more injections of electrical charges within a period of less then 20 s, the Venus flytrap upper leaf closes as soon as the total of 14 µC charge is transmitted. Similar phenomenon was reported by Czaja,29 who determined the intensity of threshold stimuli to be 2.4 µC for a closing electrostimulation of another carnivorous plant Aldrovanda vesiculosa, and 0.91 µC for an opening electrostimulation. Our attempts to open the Venus flytrap upper leaf by changing polarity of injected charge and increasing the charge from 14 µC to 100 µC were not successful. Usually, the trap opens a few days after closing in the same way as after mechanically stimulated closing.Previous work by Brown and Sharp24 indicated that electrical shock between lower and upper leaves can cause the Venus flytrap to close, but in their article, the amplitude and polarity of applied voltage, charge and electrical current were not reported. The trap did not close when we applied the same electrostimulation between the upper and lower leaves as we applied between a midrib and a lobe, even when the injected charge was increased from 14 µC to 750 µC. It is probable that the electroshock induced by Brown and Sharp24 had a very high voltage or electrical current.It is common knowledge that the leaves of the Venus flytrap actively employ turgor pressure and hydrodynamic flow for fast movement and catching insects. In these processes the upper and lower surfaces of the leaf behave quite differently. During the trap closing, the loss of turgor by parenchyma lying beneath the upper epidermis, accompanied by the active expansion of the tissues of the lower layers of parenchyma near the under epidermis, closes the trap. The cells on the inner face of the trap jettison their cargo of water, shrink and allow the trap lobe to fold over. The cells of the lower epidermis expand rapidly, folding the trap lobe over. These anatomical features constitute the basis of the new hydroelastic curvature model.20In terms of electrophysiology, Venus flytrap responses can be considered in three stages: (i) stimulus perception, (ii) signal transmission and (iii) induction of response (Fig. 1). 相似文献
7.
This paper investigates the opening and closing mechanism for the Venus flytrap (Dionaea muscipula). A mathematical model has been proposed to explain how the flytrap transitions between open, semi-closed and closed states. The model accounts for the charge accumulation of action potentials, which generated by mechanical stimulation of the sensitive trigger hairs on the lobes of the flytrap. Though many studies have been reported for the Venus flytrap opening and closing mechanism, this paper attempts to explain the mechanism from nonlinear dynamics and control perspective.Key words: Venus flytrap, modelling, kinetics 相似文献
8.
Alexander G. Volkov Shawn L. Harris II Chrystelle L. Vilfranc Veronica A. Murphy Joseph D. Wooten Henoc Paulicin Maia I. Volkova Vladislav S. Markin 《Journal of plant physiology》2013
Biomechanics of morphing structures in the Venus flytrap has attracted the attention of scientists during the last 140 years. The trap closes in a tenth of a second if a prey touches a trigger hair twice. The driving force of the closing process is most likely due to the elastic curvature energy stored and locked in the leaves, which is caused by a pressure differential between the upper and lower layers of the leaf. The trap strikes, holds and compresses the prey. We have developed new methods for measuring all these forces involved in the hunting cycle. We made precise calibration of the piezoelectric sensor and performed direct measurements of the average impact force of the trap closing using a high speed video camera for the determination of time constants. The new equation for the average impact force was derived. The impact average force between rims of two lobes in the Venus flytrap was found equal to 149 mN and the corresponding pressure between the rims was about 41 kPa. Direct measurements of the constriction force in the trap of Dionaea muscipula was performed during gelatin digestion. This force increases in the process of digestion from zero to 450 mN with maximal constriction pressure created by the lobes reaching to 9 kPa. The insects and different small prey have little chance to escape after the snap of the trap. The prey would need to overpower the “escaping” force which is very strong and can reach up to 4 N. 相似文献
9.
The Venus flytrap (Dionaea muscipula Ellis) captures insects with one of the most rapid movements in the plant kingdom. We investigated trap closure by mechanical and electrical stimuli using the novel charge-injection method and high-speed recording. We proposed a new hydroelastic curvature mechanism, which is based on the assumption that the lobes possess curvature elasticity and are composed of outer and inner hydraulic layers with different hydrostatic pressure. The open state of the trap contains high elastic energy accumulated due to the hydrostatic pressure difference between the hydraulic layers of the lobe. Stimuli open pores connecting the two layers, water rushes from one hydraulic layer to another, and the trap relaxes to the equilibrium configuration corresponding to the closed state. In this paper we derived equations describing this system based on elasticity Hamiltonian and found closing kinetics. The novel charge-injection stimulation method gives insight into mechanisms of the different steps of signal transduction and response in the plant kingdom.Key words: hydroelastic model, electrical signaling, electrophysiology, hydroelastic curvature, venus flytrap, ion channels, water channels 相似文献
10.
James O. Luken 《Restoration Ecology》2005,13(4):678-684
Carolina bays are depression wetlands of high conservation value that occur across the Southeastern Coastal Plain of the United States. Venus flytrap (Dionaea muscipula) is one rare carnivorous plant that grows in open habitats on the rims of Carolina bays. Without frequent burning, vegetation on bay rims becomes dominated by evergreen shrubs and Venus flytrap populations decline. This project examined the utility of mechanical mowing, soil clearing, transplanting, and seeding as an approach to restoring populations of Venus flytraps when fire is precluded. Mowing of patches on bay rims produced open sites with little ground‐layer vegetation. After two growing seasons, adult Venus flytraps transplanted to mowed patches showed high survivorship and relatively high leaf number/plant. Suppressed Venus flytraps existing on‐site quickly initiated growth in response to mowing. These volunteers and the transplants had higher flowering percentages than plants in reference populations. Seeds of Venus flytraps were scattered in mowed and cleared plots. Seedling establishment was low, but seedlings persisted into the second growing season. Mowing created suitable habitat for growth and flowering of adult Venus flytraps and facilitated establishment of two other carnivorous species, Sundew (Drosera capillaris) and Bladderwort (Utricularia subulata). But, mowing and clearing also facilitated invasion by four species of grasses and rushes; evergreen shrubs resprouted quickly after mowing. Maintaining persistent openings by mowing the rims of Carolina bays will be an ongoing challenge due to availability of potential invaders and rapid regrowth of shrubs. 相似文献
11.
The Venus flytrap has long been regarded as one of the most amazing examples of movement in the plant kingdom. The trapping ability of the flytrap consists of three unique features. First, trap closure represents one of the fastest movements in the plant kingdom. Second, a decision-making stage allows the plant to "decide" whether to completely close or open the trap, based on stimuli provided from the trapped object. Finally, the Venus flytrap contains a "memory function" that requires two mechanical stimuli within about 30 seconds to initiate trap closure. The movement involved in trap closure consists of nonlinear dynamics that have not been well understood. By understanding the movement, through nonlinear dynamics analysis, it will be possible to better understand this biological process. A mathematical model describing the movement of the Venus flytrap was first proposed by the authors in Yang et?al., Plant Signal. Behav. 5(8), 968-978 (2010). In the current work, the earlier research has been advanced and an in-depth nonlinear and control analysis of the dynamic process has been provided. 相似文献
12.
Marantaceae (arrowrood) are among the few examples of plants showing unexpectedly fast movements such as the ones in the meaningful mimosa or carnivorous plants. In the Venus flytrap (Dionaea), the movement of leaves is an extreme fast reaction to mechanical stimuli and based on the propagation of electrical signals. Of course, it was interesting to investigate, whether the explosively moving style of Marantaceae is based on a comparable mechanism. Electrophysiological experiments helped to understand how one of the fastest movements in the plant kingdom is mediated. 相似文献
13.
In Eukaryotes, long-distance and rapid signal transmission is required in order to be able to react fast and flexibly to external stimuli. This long-distance signal transmission cannot take place by diffusion of signal molecules from the site of perception to the target tissue, as their speed is insufficient. Therefore, for adequate stimulus transmission, plants as well as animals make use of electrical signal transmission, as this can quickly cover long distances. This update summarises the most important advances in plant electrical signal transduction with a focus on the carnivorous Venus flytrap. It highlights the different types of electrical signals, examines their underlying ion fluxes and summarises the carnivorous processes downstream of the electrical signals. 相似文献
14.
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. 相似文献
15.
Multicellular sensory hairs were excised from the leaf of Venus's flytrap, and the sensory cells were identified by a destructive dissection technique. The sensory layer includes a radially symmetrical rosette of 20–30 apparently identical cells, and the sensory cells are organized in a plane normal to the long axis of the sensory hair. The sensory cells were probed with intracellular glass electrodes. The resting membrane potential was about -80 mv, and the response to a mechanical stimulus consisted of a graded response and an "action potential." The action potential appears to be similar to the action potential which propagates over the surface of the leaf. In the absence of stimulation, the upper and lower membranes of a single sensory cell behave in an electrically symmetrical fashion. Upon stimulation, however, the upper and lower membranes become electrically asymmetrical. Limiting values for the response asymmetry were calculated on the hypothesis of an electrical model consistent with the histology of the sensory cells. 相似文献
16.
Waltraud X. Schulze Kristian W. Sanggaard Ines Kreuzer Anders D. Knudsen Felix Bemm Ida B. Th?gersen Andrea Br?utigam Line R. Thomsen Simon Schliesky Thomas F. Dyrlund Maria Escalante-Perez Dirk Becker J?rg Schultz Henrik Karring Andreas Weber Peter H?jrup Rainer Hedrich Jan J. Enghild 《Molecular & cellular proteomics : MCP》2012,11(11):1306-1319
17.
In his recent opus magnum review paper published in the October issue of Physiology Reviews, Rainer Hedrich summarized the field of plant ion channels.1 He started from the earliest electric recordings initiated by Charles Darwin of carnivorous Dionaea muscipula,1,2 known as Venus flytrap, and covered the topic extensively up to the most recent discoveries on Shaker-type potassium channels, anion channels of SLAC/SLAH families, and ligand-activated channels of glutamate receptor-like type (GLR) and cyclic nucleotide-gated channels (CNGC).1 相似文献
18.
James O. Luken 《Restoration Ecology》2012,20(6):669-670
Determining the success or failure of rare plant establishment requires long‐term monitoring, but such monitoring is seldom conducted. A 2004 census of Venus flytrap populations created by seeding and transplanting was compared to a similar census in 2010. Of the 18 original populations, three were destroyed by logging operations, 12 decreased and three increased. Venus flytraps face several limitations keeping populations small. Consistent soil moisture and the presence of population remnants improved the long‐term management outcomes. 相似文献
19.
《Bioscience, biotechnology, and biochemistry》2013,77(2):346-348
The carnivorous plant Dionaea muscipula (Venus’s flytrap) secretes proteinases into the digestive fluid to digest prey proteins. In this study, we obtained evidence that the digestive fluid contains a cysteine endopeptidase, presumably belonging to the papain family, through inhibitor studies and partial amino acid sequencing of the major SDS–PAGE band protein. The name “dionain” is proposed for the enzyme. 相似文献