Plants may experience 'optical illusions' that affect their direction of growth

A groundbreaking study from Tel Aviv University has uncovered how plants, despite lacking a brain or nervous system, can perceive light patterns in a manner that causes optical illusions and influences their growth direction. The research, led by Aharon Kempinski, Dr. Amir Porat, Dr. Mathieu Rivière, and Professor Yasmine Meroz, demonstrates that plants integrate light from various directions through a distributed sensory system, akin to a network rather than a centralized processing unit.

Light receptors distributed along the stem localise and interpret light intensity, leading to growth adjustments that may differ from the strongest illumination. This phenomenon, termed a "perceptual distortion," arises because the plant's response to light is nonlinear, meaning that a double intensity of light does not result in a biologically processed signal twice as strong.

When multiple light sources interact, plants combine these signals after local processing, resulting in growth directions that deviate from the simple addition of light sources' intensities. The mathematical model used in the study accurately forecasts how plants bend under differing light conditions, including the subtle deviations from the direction of maximum illumination, although these minor distortions could not be directly measured in the experiment.

Professor Meroz notes that this research highlights how the physical organization of a sensory system can dictate an organism's perception and response to its environment, a principle potentially applicable to various other living systems. The study was published in the Proceedings of the National Academy of Sciences, emphasizing the complex ways in which plants utilize local sensing to navigate their surroundings without a central nervous system.