Plants don't think, they grow: The case against plant consciousness. If a tree falls, and no one's there to hear it, does it feel pain and loneliness? No, experts argue in an opinion article publishing on July 3 in the journal Trends in Plant Science. They draw this conclusion from recent research which explores the evolution of consciousness through comparative studies of simple and complex animal brains. Source 9h.
I also wonder about it, as been mention plant can adapt and I think learn, with all that different chemicals and adaptation to fight off their harmful predator, or attract their prey to spread their seed or pollen or to eat them like carnivore plant, I also know plant can communicate through chemical contact between plant, and since they do have electrical signal, cannot exclude the possibility yet that they don't have consciousness as I don't think it need to be literally brain like.