SAFETY WARNINGS
If you have any current medical condition(s) or any unknown/undiagnosed conditions that might be affected by cactus we recommend you avoid contact with them. Please click here to review safety warnings before proceeding.

Which cactus species are suitable for measurements
Electrical activity can be detected in lots of species but the following ‘rule of thumb’ may be help
♦  fast growing cactus => faster electrical activity
♦  slow growing cactus => low frequency of oscillations

Where to make electrical connections
A basic measurement can be done by making electrical connections to main stem and branch. Then moniting for electrical signals over time.

How to make electrical connections to cactus
Many species of cactus have soft skins/body so (inert) needle type electrodes can inserted to make electrical connections.
Homemade electrodes can be made from blunt stainless steel darning needles which are (relatively) chemically inert and low cost.

Darning needles can be carefully inserted into larger cactus. For example, Aloe Vera, see below:

For smaller or delicate cactus subdermal needle electrodes (with twisted cables) are available from medical suppliers but should only be used by experienced & competent users due to risk of needle-stick injury.

GVB-geliMED (Germany)

unimed (UK)

 

Example cactus recording

Click here for example records with Aloe Vera and Sansevieria.


Background electrical noise

Without shielding (click here for guide to Faraday Cage) background electrical noise is noticeable. Measuring cactus signals of lower amplitude than the background noise can be challenging.


Additional information

Plant neurobiology: an integrated view of plant signaling

 

Commercial measurement equipment
Electrophysiology equipment is available from several suppliers. For example: www.wpiinc.com

 

Cactus signal analysis

For guidance on understanding plants’ electrical signals please click here.