Touch sensitivity in plants: be aware or beware.

A recent paper shows that touch sensing and gravity sensing interact to guide roots around obstacles. Upon encountering an object, the touch stimulus induces curvature behind the root tip and partially suppresses the gravity response, enabling the root to navigate around the obstacle while maintaining contact with it. These findings raise questions regarding the nature of touch sensing in roots, the location of the sensors, and the manner in which these sensory systems interact to accomplish obstacle avoidance.