REALLY?

Do plants feel pain? When a tree is pruned, for example, does it suffer?

“The answer depends on what one considers the phrase ‘feel pain’ to mean,” said Dr. Amy Litt, director of the plant genomic program at the New York Botanical Garden in the Bronx.

Animal pain depends on having brains, nerves and so forth. “Plants don’t have these,” she said. “Therefore we can say they don’t feel pain.”

But plants do respond to being damaged or attacked, Litt added. “If you define feeling pain as showing a response to a part of you being chopped off, then you could say they do feel pain.”

When a plant is wounded, perhaps by a gnawing insect, the short-term response is the release of an airborne chemical signal that is detected by the rest of the plant as well as by neighboring plants.

The signal essentially warns of danger and the need to activate cellular defense mechanisms, Litt said.

Over the long term, a plant that has been pruned might compensate and adapt by producing new shoots or buds. But whether this helps the plant or harms it depends on the species, the parts of the plant that are removed, growing conditions and time of year.

Moving from plants to lower animals, Litt suggested that “you could also ask whether things like jellyfish feel pain.”

Jellyfish have an extremely simple nervous system and no brain. Yet they respond to stimuli that might be interpreted by animals as painful, she noted, often by pulling back in the way a human being would.

“So you can interpret that as feeling pain,” she said. “Or are they only aware of being poked ?”