Plants 'can think and remember'

The Society for Plant Neurobiology was formed after the First International Symposium on Plant Neurobiology was held in Florence in 2005. This, and each of the subsequent symposia, were scientifically energizing and exciting, drawing a diverse array of participants.

Plant Neurobiology describes a newly named, but also old and fascinating field in plant biology addressing the physiological basis of adaptive behavior in plants. Perhaps this field could be called "Sensory Biology in Plants" or something similar. However, these names don't quite cover topics like plant cytology and anatomy, adaptive plant behavior, signaling and communication in symbiosis and pathogenesis, or newly emerging topics like for instance plant immunity, plant memory and learning, plant-plant communication, as well as plant intelligence.

Our choice of the term Plant Neurobiology is described in Brenner et al. (2006) where we note some obvious analogies between classical neurobiology and some aspects of the physiology of plants. For example, plants have long been known to respond sensitively to environmental stimuli by movement and changes in morphology, to be electrically excitable, to display rapid electrical responses (action potentials) to environmental stimuli, to synthesize numerous organic molecules that act as neurochemicals in other organisms, and to use hormonal signaling pathways to coordinate development, morphology and thus, accomplish behavioral responses to environmental, communicative, and ecological contexts.

For a better understanding of the world around us, it is important that we develop and share the growing understanding of plants as dynamic and highly sensitive organisms. No longer can plants be viewed and portrayed as passive entities merely subject to environmental forces, as 'automata'-like organisms based only on reflexes and optimised solely for accumulation of photosynthate. With a fuller understanding of signaling and communication within and among plants, it becomes clear that these sensitive biological organisms actively and competitively forage for limited resources, both above and below ground. In addition, plants accurately compute their circumstances, use sophisticated cost benefit analysis, and they take tightly controlled actions to mitigate and control diverse environmental stressors. Plants also emerge as capable of discriminating positive and negative experiences, and 'learning' from their past experiences. Plants use this cognitively acquired information to update their behavior in order to survive present and future challenges of their environment. Moreover, plants are also capable of refined recognition of self and non-self, and are territorial in behavior.

This Plant Neurobiological view sees plants as information-processing organisms with complex communications of various types occurring throughout the individual plant. What we need to find out is how their information is gathered and processed, what routes do data take (if not via 'nerves' sensu strictu), and how are adaptive responses integrated and coordinated, how are these events 'remembered' in order to allow realistic predictions of future using past experiences.

Last but not least, plants are as sophisticated in behavior as animals but this potential has been masked effectively because it operates on time scales many orders of magnitude slower than in animals. At the very least, this quality should make it easier for experimental plant scientists to uncover the mysteries of their neurobiological function and behavioral responses.


Reference:
Brenner E, Stahlberg R, Mancuso S, Vivanco J, Baluška F, Van Volkenburgh E (2006) Plant neurobiology: an integrated view of plant signaling. Trends Plant Sci 11: 413-419

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Abstract:

This year celebrates the 200th aniversary of the birth of Charles Darwin, best known for his theory of evolution summarized in On the Origin of Species. Less well known is that, in the second half of his life, Darwin’s major scientific focus turned towards plants. He wrote several books on plants, the next-to-last of which, The Power of Movement of Plants, published together with his son Francis, opened plants to a new view. Here we amplify the final sentence of this book in which the Darwins proposed that:

“It is hardly an exaggeration to say that the tip of the radicle thus endowed [with sensitivity] and having the power of directing the movements of the adjoining parts, acts like the brain of one of the lower animals; the brain being seated within the anterior end of the body, receiving impressions from the sense-organs, and directing the several movements.”​

This sentence conveys two important messages: first, that the root apex may be considered to be a ‘brain-like’ organ endowed with a sensitivity which controls its navigation through soil; second, that the root apex represents the anterior end of the plant body. In this article, we discuss both these statements.

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spurr said:

FWIW:

I just noticed a co-author, Stefano Mancuso, of the paper I just uploaded "The ‘root-brain’ hypothesis of Charles and Francis Darwin: Revival after more than 125 years", is the same guy who gave the TED talk CT Guy and you posted about: Stefano Mancuso: The roots of plant intelligence

Neat!

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MrFista said:

Sam - I considered MJ did not share the same phototropic responses as Arabidopsis after I posted. Thanks for clearing that up for me.

I did not intent the comment concerning pseudo science to be aimed at you, my apologies it seemed that way.

Edit - whoever finds this post 'unhelpful' can kiss my butt - I move the goalposts as I learn and make no apologies for being wrong.

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IncredibowlBoss said:

After talking about this with some friends who work in cognitive science, I think a distinction needs to be made between 'intelligence', 'cognition', and 'consciousness'. Intelligence, as an ability to store, recall, evaluate, and compare data, can be accomplished without cognition or consciousness - by computers (digital and mechanical), chemical compounds, and possibly/arguably/questionably plants.

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