Sea Rocket plants can recognize their siblings and will stop competing with them for food.

In 2007, researchers Susan Dudley and Amanda File from McMaster University studied the Sea Rocket plant. They found that plants in pots with strangers grew many more roots than plants in pots with siblings. This behavior shows that plants can identify their relatives and change how they grow to help them.Plants recognize each other using chemicals called root exudates. These are special fluids that roots leak into the soil. A 2009 study on a plant called Arabidopsis thaliana confirmed that these chemical signals help plants tell the difference between family and strangers. This process is called kin selection.Other plants use different signals to help their family. The Great Basin sagebrush sends out chemicals through the air when it is being eaten by insects. Nearby relatives pick up these signals and start making their own chemicals to protect themselves. Unrelated plants nearby do not react as strongly to these warnings.Scientists at the University of Delaware found that these signals are made of specific proteins and sugars. By helping their relatives survive, plants make sure their family genes continue to exist. These studies show that plants are not passive and have complex ways of interacting with each other.