Volkov, Alexander , Adesina, Tejumade , Jovanov, Emil .
Electrophysiology of Venus flytrap (Dionaea muscipula Ellis).
Electrical signaling and rapid closure of the carnivorous plant Dionaea muscipula Ellis (Venus flytrap) have been attracting the attention of biophysicist and electrophysiologists since the nineteenth century [1,2]. When an insect touches the trigger hairs of the Venus flytrap, mechanosensors on these trigger hairs generate an electrical signal that acts as an action potential which activate the motor cells. Six trigger hairs protruding from the upper leaf epidermis act as mechanosensors, with three of the trigger hairs located in the center of each half of the lamina. The exact mechanism of Venus flytrap closure is still unknown. Moreover, a traditionally used slow data acquisition systems cannot capture plant electrical signals with frequencies higher than half of the sampling frequency. Using an ultra-fast data acquisition system with measurements in real time, we found that action potentials in the Venus flytrap have an average speed of 10 m/s with a duration time of about 1.5 ms and are fast enough to induce the closure of the leaves by the motor cells. A few minutes after closing of the Venus flytrap, electrical signaling was also detected in the lower part of the leaf of the Venus flytrap in the form of graded potentials with amplitudes of 20 mV or less. In terms of electrophysiology, Venus flytrap responses can be represented as the following sequence: stimulus perception, signal transmission, and induction of response. We discovered that the electrical impulse between a midrib and a lobe allows the Venus flytrap leaf to close by activating motor cells without mechanical stimulation of trigger hairs. The average closing time of Venus flytraps by electrical stimulation of motor cells is 0.3 s, which is the same as mechanically induced closing by a small piece of a gelatin or cotton thread. Our results demonstrate that electrical stimulation can be used to study mechanisms of fast activity in motor cells of the plant kingdom.
1 Ksenzhek OS, Volkov AG (1998) Plant Energetics, Academic Press, San Diego
2 Volkov AG (Ed.) (2006) Plant Electrophysiology, Springer, Berlin, New York
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1 - Oakwood College, Chemistry and Biochemistry, 7000 Adventist Blvd., Huntsville, Alabama, 35896, USA
2 - Oakwood College, Chemistry and Biochemistry
3 - University of Alabama in Huntsville, Electrical and Computer Engineering
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM