Memory in Plants

In times of stress, plants typically respond to the environment and return to a normal state after the stress has passed. After the stress has passed the plant 'forgets' the previous state. It is thought that stress memories in times without actual stress may devote too much energy to responses, hindering the plants potential development and yield. Currently, research on this forgetting or 'resetting' is focused on changes in RNA metabolism, posttranscriptional gene silencing, and RNA-directed DNA methylation that help the plant in returning to a pre-stress state. Studying how these activities promote resetting could also be the key to how plants experience 'hardening' or 'remember' stressful situations to either react accordingly or ignore non-threatening stress. I was very interested to read about the numerous changes in life processes that plants make in order to adapt to stress and also return to a normal state. As plants, they are typically thought of as simple organisms with only the purpose of photosynthesis and reproduction, however this article opened my eyes to some of the other complex abilities of plants.

A plant called the Touch-Me-Not curls its leaves when it experiences physical stimulation, as seen in the gif above. Scientists at the University of Western Australia recently explored the ability of the Touch-Me-Not plant to form a memory, in order to prevent the recoiling of being touched. They found that after constant non-damaging exposure to physical stimulation, the Touch-Me-Not plant stopped curling its leaves and 'remembering' that the touch would not hurt it. By remembering not to flinch at touch, the Touch-Me-Not plant is able to conserve energy for other life processes instead of wasting it on curling from a non-threatening touch. This change in behavior and memory to do so raises the question of what changes within the plant allow this activity, opening doors for further research on the topic.