Filling in the gaps: perceptual completion in pea plants

Pea plants are climbing plants that are able to detect a potential support and flexibly adapt their approach-to-clasp movement properly. In nature, however, the complete perception of potential supports could be hidden by several above- and below-ground elements. In such circumstances, plants need to perform some sort of perceptual “completion” to produce a unified perception of their target elements. Here, we tested the existence of perceptual completion process in pea plants by analyzing their approach behavior using three-dimensional (3D) kinematic analysis. Plants were tested in the presence of a support divided into two parts located in opposite positions. One part was grounded and only perceived by the root system. The other part was raised from the ground so that only the aerial part was accessible. Control conditions were also included. The results showed that the plants integrated the information coming from the two parts of the supports to clasp it properly. We suggested that perceptual completion in plants may be achieved by a complex signaling network between the root system and the aerial sectors, allowing the establishment of a unified percept. These findings extend our knowledge of plant behavior and cognition, and provide further insights into understanding the different behavioral strategies that plants use in response to different environmental cues.