Plants have no brain or nervous system, yet a new study from Tel Aviv University suggests they can be fooled by light in much the same way that animals are fooled by optical illusions. Researchers led by Kampinsky, Porat, Rivière and Prof. Yasmine Meroz found that sunflower seedlings combine light signals from several directions in a way that does not match simple expectations, and that their growth can be pulled off course as a result.
The team tracked sunflower seedlings for more than 20 hours under blue light. The plants' light receptors sit in the outer layer of the stem and sense light locally, and those local signals are converted into biological signals that are then summed across the plant. The bending response was not proportional to the difference in light intensity between sides, which means the plants respond in a nonlinear fashion.
To test this, the researchers built a mathematical model and used it to predict how seedlings would bend under different lighting setups. In one arrangement, two equal lights pushing from opposite sides canceled each other out, and the seedlings grew toward a weaker third light. The model also predicts that plants may perceive the direction of light as slightly off from its true maximum. That distortion is the proposed optical illusion, and it has not yet been measured directly.
The study, published in the journal PNAS, leaves open whether the same principle applies to individual cells or even to bacteria. The researchers' findings suggest that plant behavior depends on how light signals are integrated across the whole organism, a process that can produce surprising outcomes even without any central processing organ.
Credit. Based on reporting for Tel Aviv University. Is this your work? Write to us.
6
