Michael Marshall,, writing in The New Scientist (Nov 2010), says 80% of tomato plants are colonized by fungi that form a network of white threads, called mycorrhizae, hanging off the roots.
These threads take in water and nutrients--but they also help the plant exchange info with other plants.
Some Chinese researchers at the South China Agricultural Univ in Guangzhou, grew pairs of tomato plants in pots, allowing some to form the networks between their roots.
Then they gave a blight to some plants--and in the network ones, the blight was milder--the plants had communicated about it and developed resistance.
They started calling the fungus "the internet of plant communities."
Intensively farmed plants, with fertilizer and care, don't seem to bother to form the fungus networks, perhaps making them less healthy.
In Canada, researchers found a network weaving its way through an entire forest, each tree connected to others.
Wonder what they are saying about us as we stomp overhead.
Maybe: "Watch out! Vegan!"