hi dear Adil Hussain      

first I should thanks for your greet answer. I talk about root to shoot communication that cause plant movement such as nastic movement or stomata closer. I will be glad if you give me information about this instrument and its cost. how we can bye that or make that.

thank you

Nabi

Hi Nabi,

a very simple measurement can be done by placing your plant into a Faraday cage, piercing two thin Pt wires(electrodes)  through the stem and connect the wires to a voltage amplifier, one to the ground and the other to the signal input. If you can trigger an electric response in your plant, a biphasic signal will be recorded some minutes or hours (!) after your trigger pulse (heat or draught pulse). The signal at the amplifier will be caused by kind of action potential travelling through the stem and changing the electrodes  potentials resulting in a deflection first to one direction (+ or -) followed by a potential change in the other direction. The amplitude of the potential changes depends on how close your electrode wires are located to the cells or tissue that carry the "action potentials". To document the signal you may also need an AD converter to store the recordings on a computer. A chart recorder would do the job, too, but doesn't allow you to change the scalings of your recordings afterwards. You may get an overview of some basic electrophysiology equipment (e.g. voltage amplifier) at www.wpiinc.com. A basic set-up may cost you ca. US$ 3000-5000. After preliminary experiments, the performance (e.g. signal-noise ratio, stability of the signal) can be improved by fabrication and use of Ag/AgCl-microelectrodes. Parts of the equipment like Faraday cages can be built by yourself but I would recommend to buy amplifiers and AD converters although you can find some circuits for amplifiers in the internet (e.g. http://neurotechzone.com/posts/1126). The commercial amplifiers contain optimised and tuned parts.

Godd luck

Gerhard

thanks for your best answer  Gerhard Obermeyer

An excellent italian researcher (Stefano Mancuso)  studies these topics. I suggest some his interesting papers. One is available at http://www.linv.org/images/papers_pdf/trends%20plant%20sci%202006%20brenner.pdf ("Plant neurobiology: an integrated view of plant signaling").

thank you dear Maurizio Micheli    

Hi,

Just a comment: I'm interested in this topic, and coming from the electronic measurement angle. I'll check out the references on how to do the measurements. 

I'm interested to hear of anyone with practical first hand experience in measuring electrical signals. What kind of amplifier did you use ? Voltage levels and frequencies ? 

i.e. use of Faraday cage etc..

Heiko

Hi: you can download some of my articles about electrical potential measuring in fruit trees. In matherial and methods is very well described how you can measure those signals. Basically you need Ag/AgCl electrodes that you can insert into the stem to reach xylem (that is for variation potential measurements). If you want to measure in phloem (por action potential for example) you will need and "aphid microelectrode" or surface electrodes. You also need an amplifier of course. There are many articles about this (search the works that belong to Dr. mancuso, Dr. Volkov, Dr. Fromm, Dr. Gurovich, etc).

Hi Pilar M Gil 

first I should thank you for your answer. Can you send me that files?? material and methods of your article?

thank you

Dear Sir,

              Please read the following paper in attached file

thank you  James DeMeo

Electrical excitability and signalling, frequently associated with rapid responses to environmental stimuli, are well known in some algae and higher plants. The presence of electrical signals, such as action potentials (AP), in both animal and plant cells suggested that plant cells, too, make use of ion channels to transmit information over long distances. In the light of rapid progress in plant biology during the past decade, the assumption that electrical signals do not only trigger rapid leaf movements in ‘sensitive’ plants such as Mimosa pudica or Dionaea muscipula, but also physiological processes in ordinary plants proved to be correct. Summarizing recent progress in the field of electrical signalling in plants, the present review will focus on the generation and propagation of various electrical signals, their ways of transmission within the plant body and various physiological effects.

In general, two different methods are being used to measure electric potentials in plants, viz. extracellular and intracellular recording. Extracellular potential measurements on the surface of higher plants have been widely performed in the past, and offer the advantage of being able to detect electrical potential differences over long periods of time (several days). By contrast, intracellular measurements with penetrating glass microelectrodes are only effective for short periods of time such as 1–2 h, because some of the electrolyte within the electrode usually diffuses into the cell to be measured and changes its original bioelectric condition. However, intracellular recording has theadvantage of being more precise because membrane potentials and electrical signals may be deduced from specific cells.

Hi,

You may also find detailed method for surface electrical signals measurement on Arabidopsis leaves from the articles that recently published in Nature 

http://www.nature.com/nature/journal/v500/n7463/full/nature12478.html

http://www.nature.com/nature/journal/v500/n7463/full/500404a.html

http://www.nature.com/nprot/journal/v9/n8/abs/nprot.2014.136.html