Researchers have long speculated about whether plants are capable of interacting with humans and each other. One study found that they sometimes ‘talk’ to each other through the soil. Now scientists from the University of Western Australia (UWA) have discovered an intriguing new aspect of plant life: they appear to respond to touch.
There’s no visible sign that plants respond to touch, according to the scientists, who recently released their research in the journal Plant Physiology. Instead, the researchers noticed how plant genes expressed themselves differently after being sprayed with water. The gene changes happened minutes after they were sprayed and only lasted for around half an hour. The scientists determined there were no ‘active compounds‘ that might trigger a change; demonstrating that the plants changed in response to their external environment.
Gene changes in the plants happened not only when they were sprayed with water, but when humans touched them with fingers or tweezers and even when shade fell across them. Lead researcher Olivier Van Aken said it could happen naturally when it rains, when the wind blows, or when a bug skitters across a plant.
Van Aken said, “Although people generally assume plants don’t feel when they are being touched, this shows that they are actually very sensitive to it and can redirect gene expression, defense, and potentially their metabolism because of it.”
Why might plants respond this way? It appears they may be protecting themselves or even adapting to environmental conditions, such as increased water or light.
Van Aken said, “Unlike animals, plants are unable to run away from harmful conditions. Instead, plants appear to have developed intricate stress defense systems to sense their environment and help them detect danger and respond appropriately. The findings may cause us to think differently about our interactions with the plants around us. While plants don’t appear to complain when we pinch a flower, step on them, or just brush by them while going for a walk, they are fully aware of this contact and are rapidly responding to our treatment of them.”