Plants may just be smarter than you think, according to a new study by an international team of researchers, published in Current Biology this week.
By studying the decisions plants made when presented in environments with different nutrient levels, plants showed a remarkable ability to take calculated risks in order to secure the maximum amount of nutrients.
"To our knowledge, this is the first demonstration of an adaptive response to risk in an organism without a nervous system," said Oxford University’s Alex Kacelnik in a press release.
In order to evaluate plants’ decision making skills, researchers grew pea plants with their roots split between two pots with varying levels of nutrients. First, scientists found that plants chose to grow more roots in the pot with more nutrients.
Then, scientists examined plant behavior when one of the pots offered a consistent level of nutrients, but the other pot varied widely.
While both pots offered the same amount of nutrients on average, when the average nutrient level was high in the consistent pot, plants chose that pot. Yet, plants chose to grow more roots in the pot with a varied level of nutrients when the consistent pot offered a low amount of nutrients, demonstrating a willingness to take calculated risks.
“Complex and interesting behaviours can be theoretically predicted as biological adaptations, and executed by organisms,” said Dr. Kacelnik, “on the basis of processes evolved to exploit natural opportunities efficiently."
Scientists are still unsure of the plants sense variance, but they are nevertheless surprised by the decision making skills that the plants evidently possess.
"I used to look at plants as passive receivers of circumstances," says Efrat Dener, of Ben-Gurion University in Israel. "This line of experiments illustrates how wrong that view is: living organisms are designed by natural selection to exploit their opportunities, and this often implies a great deal of flexibility."
Researchers have been digging up evidence that plants are wiser than we might imagine for some time.
In 2005, The Christian Science Monitor reported that plants are capable of considering their environments and planning for the future.
Strangleweed, for example, can sense “friends, food, and foes.” There's evidence to suggest that plants can develop their own "personalities" – identical cuttings from the same “mother” plant develop different characteristics when planted separately, despite being raised in the same conditions.
"If intelligence is the capacity to acquire and apply knowledge, then, absolutely, plants are intelligent," University of Utah biologist Leslie Sieburth told the Monitor in 2005.
Some biologists say that decision-making skills alone do not make plants intelligent, and that in order to be truly intelligent, plants also must have self consciousness.
Still, the study of plant intelligence is a growing field, and scientists say that lessons learned from the study of human and animal decision making are transferrable to the study of plant behavior, which has fascinating implications for future study.
"To see that decision-making models developed by economists for human decision makers,” said Hagai Shemesh of Israel's Tel-Hai College, “and by zoologists to understand animal behavior can predict the behavior of plants facing similar choices is fascinating."
The next step, scientists say, is presenting plants with tasks that require them to adapt to different circumstances.