Plants may lack brains, but they have a nervous system, of sorts. And now, plant biologists have discovered that when a leaf gets eaten, it warns other leaves by using some of the same signals as animals. The new work is starting to unravel a long-standing mystery about how different parts of a plant communicate with one another.
Animal nerve cells talk to each other with the aid of an amino acid called glutamate, which—after being released by an excited nerve cell—helps set off a wave of calcium ions in adjacent cells. The wave travels down the next nerve cell, which relays a signal to the next one in line, enabling long-distance communication.
I don't get why anyone would ever have seen the world as a binary separation between entities that "have feelings" and those with "no feelings at all". It's all a sliding scale of varying capacity to sense, interpret and express responses to external stimuli.
Of course plants have "feelings", for a certain interpretation of the word. They have a desire to live, grow, thrive, and reproduce. They react to changes in their environment and adapt their behaviour based on coming into harm and sustaining damage. A plant is never going to cry or scream out in pain but as a living organism it is obviously going to be aware that this is happening and on some level would rather it didn't!