Gently rubbing your plants’ leaves can stimulate them to resist disease, according to a new report. When scientists rubbed the leaves of a thale cress plant, the leaves produced biochemicals that made the plant more resistant to the fungus that causes grey mold. So, don’t bother talking to your plants: Pat them instead!
How does that work? The rubbing is a kind of mechanical stress, and the plant reacts as if it has been physically wounded. Although the leaf cells are not harmed, they respond even to a gentle touch as if they were. The leaves becomes more permeable, and molecules that contribute to an immune response to limit infection rise to the surface. You can read the full story at “Perception of soft mechanical stress in Arabidopsis…” in BMC Plant Biology, 2013.