Zigzagging plants

Play a recording of growing plants at high speed, and you will see plant spinning on their stems. Now a group of international researchers show in Physical Review X that plants doing this avoid the shade of their neighbours.

The spinning movements from plants we mainly observe by climbing plants. Those try with their tendrils to find a handhold. During this process we see the tendrils sometimes located towards the right, and sometimes towards the left, like a drunk that tries to find something steady. But other plants also make circumnutations. The researchers wanted to find out why.

The researchers grew sunflowers closely together. During this the researchers filmed their movements from the top. In this way they could follow the spinning tops of the plants. They noticed that the plants did not spin in a fluent movement. In stead the spinning was sometimes slow, and sometimes fast.

Plants spin to receive more sunlight

Subsequently the researchers used the recordings of twelve repeats to make a model of the growth. After that they could adjust the parameters of the model. In this way the researchers could get the plants to spin slower or quicker.

By doing this the researchers discovered that when the plants hardly moved, they were constantly for a part in the shade of their neighbours. This was in sharp contrast with the plants that the researchers recorded. Those plants were able to get away from the shadow of their neighbours. It turned out that they could do this because their zigzagging growth. Each time they moved they did this in exactly the opposite direction as their neighbour. In this way most of the sunlight could reach their leaves.

But when the researchers spinned the plants in the simulation faster than that what was observed. Then the plants were unable to coordinate their zigzag growth in tune with their neighbours. They got more shade.

Literature

Chantal Nguyen, Imri Dromi, Ahron Kempinski, Gabriella E. C. Gall, Orit Peleg, and Yasmine Meroz (2024) Noisy Circumnutations Facilitate Self-Organized Shade Avoidance in Sunflowers. Phys. Rev. X 14, 031027 https://doi.org/10.1103/PhysRevX.14.031027

Zigzagging plants