Arabidopsis Rapid Movement Response to Electrical Stimulation

Objective: Plants respond to their environment in a multitude of ways. Gradual movements occur in response to light (phototropism), and more rapid movements occur in response to touch (thigmatropism). In this report, we describe a rapid movement response that occurs in plants without any physical contact with the seedlings that is based on electric charge.

Methods: Three varieties of seeds were planted in the laboratory under sterile conditions. After 5-10 days the seedlings were tested for their response to electric field stimuli, and video responses were recorded.

Results: Plant seedlings of Thymus vulgaris, Arabidopsis thaliana and Mentha spicata, starting at the 2 or 3 leaf stage, were capable of msec movement responses to objects that conveyed an electric charge. The fluctuation in the electric field was measured with a sensor attached to an oscilloscope. The addition of a known ion channel blocker, amiloride hydrochloride, to the nutrient media inhibited the plant response in two species tested, Mentha spicata and Arabidopsis thaliana.

Conclusion: This evidence suggests that a possible mechanism for the rapid movement operates through the closure of ion channels similar to the rapid closure of the Venus flytrap.