“Plant Consciousness: The Fascinating Evidence Showing Plants Have Human Level Intelligence, Feelings, Pain and More” by Stephen Harrod Buhner:

“The similarity of human and plant neural systems and the presence of identical chemical messengers within them illustrate just why the same molecular structures (e.g., morphine, cocaine, alcohol) that affect our neural nets also affect plant consciousness. Jagadis Bose, who developed some of the earliest work on plant neurobiology and plant intelligence in the early 1900s, treated plants with a wide variety of chemicals to see what would happen. In one instance, he covered large, mature trees with a tent, then chloroformed them. (The plants breathed in the chloroform through their stomata, just as they would normally breathe in air.) Once anesthetized, the trees could be uprooted and moved without going into shock—the pain perception of the plants diminished. He found that morphine had the same effects on plant consciousness as that of humans, reducing the plant pain perception and pulse proportionally to the dose given. Too much took the plant to the point of death, but the administration of atropine, as it would in humans, revived it. Alcohol, he found, did indeed get a plant drunk. It, as in us, induced a state of high excitation early on, but as intake progressed the plant began to get depressed, and with too much it passed out. The plant felt drunk.

“Irrespective of the chemical he used, Bose found that the plant responded identically to the human; the chemicals had the same effect on the plant’s consciousness and nervous system as it did the human.

“This really should not be surprising. The neurochemicals in our bodies were used in every life-form on the planet long before we showed up. They predate the emergence of the human species by hundreds of millions of years. They must have been doing something all that time, you know, besides waiting for us to appear. Like, for example, giving plants the ability to feel, perceive and sense pain, among countless other things.”