Do plants communicate with each other, can they develop ways defend themselves, and do they react to people?
I will answer one serious part of your question, which is whether plant can develop ways to defend themselves. It might not be exactly what you were thinking of, but researchers have recently shown that plants are able to mount what are called inducible defenses in response to attack by a natural enemy (e.g., herbivore, pathogen). The coolest example that I know of & lecture about is the release of a volatile compound by plants that attracts a parasitoid of one of its herbivores. This qualifies as a biological instance of the “enemy of my enemy is my friend” hypothesis.
