by Ian Sample
July 03, 2019

from TheGuardian Website



The plant neurobiology debate

is shaping up to be the biggest botanical bunfight

since the Romantic era.

Photograph: Alamy



Environmental crisis

clouding scientific objectivity

about plants' feelings,

says botanist


The gardening gloves are off.


Frustrated by more than a decade of research which claims to reveal intentions, feelings and even consciousness in plants, more traditionally minded botanists have finally snapped.

Plants, they protest, are emphatically not conscious...

The latest salvo in the plant consciousness wars has been fired by US, British and German biologists who argue that practitioners of "plant neurobiology" have become carried away with the admittedly impressive abilities of plants to sense and react to their environments.


While plants may,

...the vexed biologists argue that is no reason to believe they choose their actions, learn along the way or occasionally get hurt in the process, as some plant neurobiologists assert.


Bothered by claims that plants have "brain-like command centers" in their root tips, and possess the equivalent of animal nervous systems, the critics counter there is no proof of sentient vegetation or structures within plants that would grant them what the neuroscientist Antonio Damasio has called,

"the feeling of what happens".

Lincoln Taiz, a botanist at the University of California, Santa Cruz, and seven like-minded researchers writing (Plants Neither Possess nor Require Consciousness) in the journal Trends in Plant Science, where plant neurobiology made its debut (Plant Neurobiology - An Integrated view of Plant Signaling) in 2006, state:

"There is no evidence that plants require, and thus have evolved, energy-expensive mental faculties, such as consciousness, feelings, and intentionality, to survive or to reproduce."

Taiz told the Guardian:

"Our criticism of the plant neurobiologists is they have failed to consider the importance of brain organization, complexity and specialization for the phenomenon of consciousness."

The broadside drew a robust response from the University of Sydney's Monica Gagliano, who conducts research on the cognitive abilities of plants, including,

  • perception

  • learning

  • memory

  • consciousness

She said the criticisms failed to take account of all the evidence and focused only on work that supported the authors' viewpoint.

"For me, the process of generating knowledge through rigorous science is about understanding the evidence base behind a claim," she said.


"Where is their experimental data? Or are we expected to just accept their claim at face value?"

Taiz draws on work by the US researchers Todd Feinberg and Jon Mallatt, who explore the origins of consciousness by comparing simple and more complex brains in animals.


They conclude that while animals ranging from insects and crabs to cats and monkeys have sufficient brains to be conscious, other organisms fail the test.

Those organisms include plants, Taiz argues.

The debate is shaping up to be the biggest botanical bunfight since the Romantic era when plant biologists argued for more than a century about sex in plants.


As the purists argued nothing so obscene would be happening in flower beds, extremists on the sex side envisioned plants not only having sex but being full of lust and passion.


Taiz believes the rise of plant neurobiology is driven by the environmental crisis that poses an ever-increasing threat to life on Earth.

"They want to raise people's consciousness about plants as living organisms and reach them on an emotional level. I'm very sympathetic to the motivations, but it is clouding their objectivity.


They have to be prepared for the fact that plants may not have consciousness," he said. "It's bad science. It takes the whole scientific enterprise and reduces its credibility."

But Gagliano is having none of it.

"If we think we already know how things are and fail to continuously question our own assumptions, but construct our claims on a system of beliefs we are dearly attached to, then we are in deep trouble and miss the opportunity for true scientific discovery to occur.


"Miserably, this opinion piece seems yet another missed opportunity, one that makes strikingly no headway towards a better scientific understanding of what consciousness is."

Where the debate leaves Prince Charles, who not only talks to his geraniums but positively instructs them, is unclear.

"Far be it from me to criticize Prince Charles, or anyone else for that matter, for talking to their plants," Taiz said. "I would indeed be concerned, however, if they ever talked back."