Plants can learn new tricks

By Jacqueline Outred 28 January 2014
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Some sleepy plants are actually quick at adapting to new experiences.

THEY MAY LOOK BENIGN, but plants are much more intelligent than we think. New Australian research has shown that plants are capable of learning new tricks.

The Mimosa pudica, known as the ‘sleepy plant’ or ‘touch-me-not’, showed adaptation to new experiences scientists presented it with, even though it has no brain.

“Learning is crucial to evolutionary adaptation and survival because the environment is constantly changing,” says lead researcher Monica Gagliano, from the University of Western Australia’s Centre for Evolutionary Biology.

“In order to adapt to everyday life, you need to be able to process information received from the environment, remember it and recall it when those conditions occur again,” Monica says. “In this context, it doesn’t make sense to keep plants separate from the learning sphere.”

Plants capable of acquired learning

Previous research had always assumed that plants could respond only in ways that were already coded into their DNA, largely because they have no brain to retain memory. “Nobody considered that plants were capable of acquired learning,” Monica told Australian Geographic.

Following her previous discovery that plants could ‘talk’ to each other, Monica wanted to further explore the similarities between plants and the animal kingdom.

To conduct her research, Monica chose the Mimosa pudica fern, which closes its leaves when touched to protect itself from predators. “We wanted to use a plant that would show easily observable behaviour,” she says.

Under controlled conditions, Monica and her team dropped the plant from a height to cause the plant to feel threatened. The impact forced the fern to respond protectively and close its leaves.

‘Scared’ plants learn quickly

“We basically tried to scare the plant,” Monica says. “The first time, it worked but the plant quickly worked out that nothing bad would happen to it, and it stopped closing its leaves.”

Varying the light levels, the researchers established that plants learn quickest under demanding conditions (low light), just as animals do.

These results, published by Oecologia earlier this month, challenge the boundaries that separate plants and animals. “The ability to memorise, learn and respond may not be as centralised to the brain as we previously thought,” Monica says.

Dr Andrew Young, plant ecologist from the CSIRO, says the research is interesting. “If plants can learn and remember as shown, then this would provide an additional layer of potential behavioural responses that they could draw on to cope with environmental changes,” he says.

Monica plans to investigate further to find out if plants are also capable of higher levels of learning.

“Deep down, we may not be as different from animals,” Monica says, “but we may not be that different from plants either.”