Plants feel when touched. They make the difference between hot and cold and know when the wind is shaking their branches. They don’t like contact.
Some experiments :
Angular cucumber experience. They are ten times more sensitive than us and perceive a filament weighing less than 0.25 grams.
Experiences Darwin, Burdon Sanderson and more recently Volkov (University of Oakwood in Alabama) on the Venus flytrap which feeds not only on photosynthesis, but also on small insects and animals. Its leaves close in on their prey in less than 1/10 of a second, thanks to the electrical activation caused by touch. There are at least 600 different kinds of carnivorous plants.
Experience of the modest Mimosa (called don’t me touch). Its leaves close as soon as it is touched, thanks to the triggering of an electrical signal. This signal activates a kind of hydraulic pump which, thanks to the action of potassium, causes the leaves to move.
Experience Salisbury then Jaffe at the end of the 20th century on the oriental xanthium and Braam of Rice University on the ear-mice cress. Touching a plant regularly slows or alters its growth and sometimes kills it. Wind also has an important influence on growth. Touching causes a rapid modification of the ear-mice cress genetic program (2% of its genes are activated when an insect, animal or the wind touches it …).
Bowles experience at the University of Leeds then Farmer at the University of Lausanne. The tomato does not seem to feel the pain (burning, intense cold, tearing). Indeed, she does not move away from the place of the injury. But on the other hand, it communicates the event to the rest of the plant and triggers the production of jasmonic acid, a defense hormone. For this, as for the nerves, it acts by electrical impulse towards the stem then towards the other leaves, but also by using proteins (very similar to those which one finds in the synapses of the neurons).