Research reveals how plants determine where light is coming from

Plants use a light-sensitive tissue to detect the origin of light and position their organs for optimal photosynthesis. This tissue generates a light gradient using the optical properties of the air-water interface. Air-filled channels in the stems enable the plant to establish the light gradient. The different refractive indices of air and water cause light scattering, which allows the plant to perceive the direction of the light source. These channels also serve other functions.