http://www.abc.net.au/news/2016-12-06/plants-can-use-memory-to-learn-uwa-study-suggests/8098142
Plants can learn despite absence of brain, UWA study suggests
Plants have memory and can learn to associate separate events based on their association with past occurrences, a West Australian researcher says.
Associative learning was previously considered to be the domain of animals, with the brain and a central nervous system considered essential in creating memories.
However, the new results from research at the University of Western Australia (UWA) could cause a change in the understanding of how animals create memories, UWA research associative professor in evolutionary ecology Monica Gagliano said.
Associative learning is an organism’s ability to create meaning between two seemingly unrelated events, much like the famous Pavlov’s Dog experiment.
Professor Gagliano’s research demonstrated plants have the ability to predict future events based on their association with past occurrences.
“When those events occur again together, you have to be able to anticipate, based on one event that was meaningless but now has meaning, what is going to happen next,” Professor Gagliano said.
“The entire question of agency, sentience, even consciousness, becomes a topic we may now be able to treat medically and scientifically.”
Professor Gagliano’s research centred around teaching pea seedlings to predict the location of a light source, by creating an association with a fan.
Seedlings were placed in a Y-shaped maze, with a light source and a fan located at the top.
The plant was exposed to the fan and then immediately to light to create an association between the two, and the results were unexpected.
Plant changed growth path in anticipation
The testing was carried out across several days, with the plant responding to its photosynthetic processes when there was no light and growing to where the light was last present.
When the fan was activated, the plant changed its growth path in anticipation the light would come from a new source.
“What that meant, for the plant to choose what the fan was indicating, the plant was required to go against its own phototropic and native instinct,” Professor Gagliano said.
“They overcame their own instinct and they trusted in a way, the message delivered by the fan and the association they had learned to move towards something that initially had no meaning whatsoever.”
She said the result was surprising.
“It is not what you would expect from an organism that does not have a brain or a central nervous system,” Professor Gagliano said.“Plants have demonstrated that a brain and a nervous system are just one way .”
The results could have a wider implication in the study of memory and brain function, as they demonstrate that memory creation may be a fundamental part of all organisms and that different species have different ways of accessing them.
Professor Gagliano believes the next step would be to look at how other organisms such as sponges, which are animals but don’t have a central nervous system or brain, create associations.