Posted by: Prospector PJ6 MAR 2013
Scientists have for some time known plants communicate with each other, but new research has revealed that plants react most strongly to messages from their genetically related neighbours.
When an insect bites a leaf, many plants release volatile chemicals that prime their neighbours for attack. This triggers various responses, from attracting predatory insects that eat the herbivores to making themselves less tasty. But for the sagebrush, response to these warning signals varies with relatedness.
A study published in New Scientist exposed sagebrush branches to volatile chemicals released by relatives of the same species. By the end of the growing season herbivores had done less damage to branches exposed to chemicals from close relatives than to those from more distant relations. The warnings had probably prompted the sagebrush to release herbivore deterrent chemicals, researchers concluded.
The same researchers have previously shown that the blend of volatiles varies enormously between individuals, while there is some similarity between family members. They suggested that this mechanism gives those that share the same genes a greater chance of survival.
Self recognition in plants has also been demonstrated by fewer competitive interactions between physically connected roots. And plants competing for space in a small pot are less aggressive if related to their neighbours.
Plant roots may communicate using clicking sounds, according to a study published in Trends in Plant Science. Researchers have recorded clickings coming from the roots of corn saplings, and when they suspended roots in water and played a continuous noise at a similar frequency to the clicks, the plants grew towards it.
Sound waves travel easily through soil and the researchers suggested that sound vibrations could help plants to gain information about their environment. They could, for example, send warning of threats such as drought from neighbours further afield.