National Geographic has story on plant intelligence that is fairly astounding, though unsurprising for those of us old enough to have followed Zonker Harris’ horticultural exploits in the late 70’s – early 80’s (somewhere thereabouts).
A prime mover in the modern field of plant intelligence is botanist Anthony Trewavas of Scotland’s University of Edinburgh, who defines intelligence as the ability to sense the surrounding environment, analyze the results, and, based on input, make decisions as to how to behave. Plants, says Trewavas, have these abilities in spades, but we tend not to notice this much since plants, in general, are slow responders. Anchored in place as they are, their prime response to external cues—such as sun, shade, water, rocks, neighboring plants, or predators—is to change their growth pattern, which isn’t always exciting.
On the other hand, there’s now evidence that plants can actively learn and form long-term memories. Australian ecologist Monica Gagliano works with Mimosa pudica, nicknamed the sensitive plant or touch-me-not because it rapidly folds up its fern-like leaves if bumped, shaken, poked, landed upon by a bug, or approached with a lighted match. In Gagliano’s lab, potted mimosas were dropped from a height of about six inches onto a foam pad—a harmless jolt that nonetheless caused the plants to nervously close their leaves. After repeated drops, however, the plants ceased to respond, having apparently analyzed the situation and determined that dropping wasn’t dangerous.
And the plants remembered their experience up to a month later. While untrained newbie mimosas panicked and clapped their leaves shut in response to the drop, the trained plants kept their leaves calmly open.